OH NO!
01-24-2004, 10:58 PM
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OH NO!
well i was on my way to Home Depot, and the trans in my car is slipping when it shifts out of 2nd into 3rd... after it recovers from the slipping the car vibrates when u press the gas!!! this is my cars 3rd transmission!!!!!!!!!! my SSE only has 81,000 miles on her. WHY ME???? its time for a new car. maybe a 92/93 SSE/i
01-25-2004, 12:44 AM
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DISTRESSED SECOND CLUTCH 440-T4/4T60 DIAGNOSIS #90-7-36 - (04/11/1990)
Models Affected: 1984-1990 6000, BONNEVILLE AND GRAND PRIX MODELS WITH 440-T4/4T60
Second clutch diagnosis tips - all 1984-90 Hydra-matic 4T60 (THM 440-T4) transaxles.
A worn or damaged second clutch in a Hydra-matic 4T60 transaxle may exhibit one of the following conditions.
1. Slips or shudders during 1-2 shift
2. Slips in second gear
3. No second gear
When diagnosing a transaxle for one of the above conditions, the following items should be checked first.
1. Test drive the vehicle to verify the condition.
2. Verify proper fluid level.
3. Verify proper transmission line pressure according to the chassis service manual procedure. Check minimum pressure by applying 18" of vacuum to the vacuum modulator (use a hand vacuum pump). Check maximum line pressure with no vacuum applied to the vacuum modulator (vacuum line disconnected). Check both minimum and maximum at 1250 RPM in each range. If there is no boost in pressure with zero vacuum, check for an inoperative vacuum modulator or modulator valve. A ruptured aneroid bellows in a vacuum modulator will result in no boost in pressure with zero vacuum applied.
Note: Do not measure maximum pressure by pulling out on the T.V. cable. 1987 and later models will give you a boosted pressure at full T.V. which is not the same as the maximum pressure reading with zero vacuum. Using the T.V. cable can give you a false maximum pressure reading and will not reveal an inoperative vacuum modulator.
4. Use a vacuum gage on the vacuum line at the vacuum modulator end to verify full engine vacuum is available at the vacuum modulator. The vacuum should register immediately as the engine is started and should respond quickly to engine load changes. When you flash the throttle from idle, the vacuum gage should drop instantly and recover as soon as the engine returns to idle. If the response is slow, check for a restriction in the vacuum line. This restriction can trap vacuum in the modulator on acceleration and cause a slip during shifts because of low boost pressures.
Remember that 1989 and 1990 Grand Prix models with 3.1L engines have a .031" orifice in the modulator end of the line. Do not enlarge or remove this orifice.
Knowing the results of the above checks will help determine the causes of a damaged second clutch once you get inside the transaxle. The second clutch is applied and carrying torque in 2nd, 3rd and 4th gear. Therefore, if fluid level or pressure is low or if the pressure does not boost when the engine is loaded, the 2nd clutch will be one of the first to slip and eventually wear or burn.
Once inside the transaxle there are several items to look for when diagnosing a damaged 2nd clutch:
1. Mispositioned 2nd clutch snap ring.
2. Split, cut or rolled 2nd clutch piston seals or damaged piston.
3. 2nd clutch housing leaking through cracks in the housing or welds.
4. Fluid leaks through 2nd clutch housing check ball or its retainer.
5. Check for deformed or damaged piston return springs in the apply ring and return spring assembly. If these springs are weak, they can allow the 2nd clutch plates to drag while the 2nd clutch is released in 1st and reverse, This can result in premature wear of the 2nd clutch plates.
Note: The piston return springs are easy to overlook but can definitely be a cause of repeat failure of the 2nd clutch.
5. 1984-1986 - driven sprocket support cast iron seals worn or broken. Check for grooves being cut into the inside diameter of the 2nd clutch drum. If so, replace the second clutch drum and install a driven sprocket support with the later style support using Vespel ring seals. 1987-1990 - driven sprocket support Vespel ring seals cracked or broken. Check for damaged or mispositioned four lobe support seals under the Vespel rings.
6. Check the 2nd clutch apply passage which between the driven sprocket support and bushing. Look for the bushing being out of position or worn. If either condition is found, the driven sprocket support should be replaced. Blow air through the passage to check for restrictions or foreign material. If full apply pressure cannot get through to the clutch, it will slip and wear.
7. Check for a leak at the sealing surface where the driven sprocket support contacts the channel plate.
General Motors bulletins are intended for use by professional technicians, not a "do-it-yourselfer". They are written to inform those technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions and know-how to do a job properly and safely. If a condition is described, do not assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See a General Motors dealer servicing your brand of General Motors vehicle for information on whether your vehicle may benefit from the information.
NO 3RD GEAR AND/OR NO DRIVE OR REVERSE #91-7-13 - (10/08/1990)
Subject: NO 3RD GEAR, AND/OR NO DRIVE OR REVERSE CENTER GEARBOX DISTRESS DIAGNOSIS TIPS
Models Affected: 1984-91 6000, BONNEVILLE, GRAND PRIX MODELS WITH 4T60 TRANSMISSIONS
BULLETIN COVERS:
Center gearbox distress diagnosis tips - all 1984-91 HYDRA-MATIC 4T60 transaxles. Center gearbox distress in a HYDRA-MATIC 4T60 transaxle may result in one of the following conditions:
1. No 3rd gear due to a distressed 3rd roller clutch cage. Also, slips in 3rd gear or no 3rd gear.
2. No drive or reverse due to a distressed input sprag.
3. Distressed 3rd and input clutch fiber and reaction (steel) plates.
Many changes were implemented to help reduce center gearbox distress. This bulletin will discuss them and reference bulletins already published on previous changes and what components should be inspected during an overhaul. Also, some other helpful tips and information about lubrication flow have been added. Reference Figures 1 and 2.
Several aftermarket publications have been written concerning different ways to modify the center gear box. Some of the modifications include grinding slots, lining up the lube holes differently, and greatly increasing the fluid level. DO NOT ATTEMPT THESE PROCEDURES! These publications were written to supposedly improve the performance of the center gear box, but instead the modifications can cause durability concerns or the procedures are not necessary.
1. Changes have been made to the 3rd roller clutch which will improve its durability. Revisions have been made to the lube holes on the outside race. Four of the lube holes have been eliminated. When the lube holes are eliminated, the the rollers are less likely to **** or skew when overrunning. When the rollers **** or skew, excessive heat is created. Reference Pontiac Service Bulletin 90-7-35 issued 4/90.
1A. To increase the lubrication to the 3rd roller clutch assembly, a 3rd roller clutch dam was added and the input housing shaft I.D. 4th clutch shaft seal was eliminated. This change occurred for the 1985-1/2 model year. Reference pages 1-7 and 1-8 in the Hydra- matic 440-T4 Product Update book.
2. New Output Shaft With A Single Path Bearing: The new output shaft and bearing allows more lubrication fluid to flow to the center of the gearbox. Reference Pontiac Service Bulletin 90-7-35 issued 4/90.
3. New 10 Plate 3rd Clutch Assembly For SOP 1989: The 10 plate clutch assembly, compared to the previous 8 plate clutch assembly, is for higher torque engine applications and also helps eliminate heat build-up due to numerous repeat manual Lo engagements at speeds around 35 MPH. Reference Pontiac Service Bulletin 89-7-2 issued 10/88.
4. End Plays: If the final drive has too much clearance, this will allow the final drive sun gear to move away from the thrust bearing in the final drive. This will allow too much lube fluid to leak out from the final drive sun gear shaft - with the correct final drive end play, the sun gear would block most of the lube fluid from escaping from the sun gear shaft. If the input housing has too much clearance, this would allow too much lubrication fluid to leak out between the input housing thrust bearing and 3rd roller clutch cam. Some leakage is designed in, but too much due to worn, damaged, missing bushings, too much end play or in- correctly installed parts could cause a durability concern. Reference the lubrication circuit fluid flow description, Figure 1.
5. The final drive sun gear lube groove must face towards the parking gear to allow adequate lubrication flow to the final drive pinions. The final drive sun gear shaft has lubrication holes in the shaft that feed fluid into the step in the sun gear, then through the two slots in the parking gear to the final drive pinions - if the final drive sun gear was installed backwards, the holes in the final drive sun gear shaft would be blocked, not allowing fluid to lubricate the final drive pinions.
6. Check lube pipes for correct installation and any damage (plastic cracked, pipes bent, etc.). Ensure the lube pipe retainer is in the proper position. A mispositioned or damaged component will leak lubrication fluid into the bottom pan instead of directing the fluid to the center of the gearbox. While bolting down the accumulator cover, inspect the position of the lube oil pipe retainer. (Reposition if cocked).
7. Fluid Foaming Due To Overfilling Or Incorrect Thermo Element Height: If the fluid level is too high, the moving parts will churn the fluid, causing the oil to foam. This will cause many durability concerns including damage to the center of the gearbox. An incorrect thermo element height will cause the fluid level to be inaccurate (either too low or too high) when the fluid is up to operating temperatures. Too low a fluid level will cause air to be sucked into the filter, and too high a level will cause fluid foaming due to churning. Check the height with thermo element height setting tool, J 34094-A.
8. 4th clutch hub and shaft assembly should have one needle missing from the inside of the bearing cage for oil flow to the 4th clutch fiber and reaction plates.
9. Cooler Flow Test - Oil cooler for the transaxle that is located in the radiator and the oil-to-air cooler (optional) that is connected in series with the radiator transaxle oil cooler: Correct flow is two quarts of fluid per 30 seconds. Also, it must be flushed; refer to Labor Time Guide for labor operations that must have the transaxle oil cooler flushed.
10. Input Housing To 3rd Roller Cam Thrust Washer Replaced With A Needle Bearing: Reference Pontiac Service Bulletin 86-7-53 issued 2/88 for details about interchangeability and past model service.
11. The lube dam must be installed on most 1986 and newer models between the input and reaction carriers. Leaving a worn, damaged or missing lube dam will allow too much lubrication fluid to leak into the bottom pan. Reference Pontiac Service Bulletin 86-7-23 issued 2/88.
IMPORTANT:
When reassembling a 3rd roller clutch, ensure that the lube dam is pressed into the proper depth. If the 3rd roller clutch is mated to the thrust needle bearing instead of the washer, then:
- press the dam to a depth of 20.72/20.92mm (0.816/0.824") as measured from the bottom side (sprag side) of the outside race to the wide flat edge of the dam as shown in Figure 3.
If using the thrust washer, press the dam (on models so equipped) to a depth of 20.04/20.12mm (0.789/0.792") as measured from the bottom side (sprag side) of the outside race to the wide flat edge of the dam as shown in Figure 3.
NOTICE: Measure the press in depth for the dam as shown in Figure 3. Measuring from the top of the 3rd roller clutch race to the dam will be inaccurate because all the machining of the 3rd roller clutch race is based on the opposite side (side that mates to the input sprag) . If the dam is pressed in too far or not far enough, it could rub on the 3rd roller clutch cage or the snap ring that retains the 3rd clutch return spring and create excess heat to distress the cage of the 3rd roller clutch.
12. Line Pressures: Lubrication fluid is proportional with line pressures. If the line pressure is below specification, then lubrication fluid flow would be inadequate. Check the line pressure as outlined in the service manual and reference Pontiac Service Bulletin 90-7-36 issued 6/90 for further details about vacuum modulator diagnosis.
13. Check converter clutch regulator valve for proper operation, binding, sediment or damage, etc. This valve controls the flow of lubrication - when the torque/viscous converter clutch (TCC/VCC) is applied, mainline lubrication fluid from the pump pressure regulator is routed past the torque converter directly to the cooler; when TCC/VCC is not applied, the fluid is routed through the converter, then to the cooler. If the valve is damaged, a new valve is included in service package 8646934 - use only the convertor clutch regulator valve from this package.
SERVICE PARTS INFORMATION:
Part Number Description Usage
8646934 Package, V.B. Spacer Plate Conv. All 1984-1991 4T60 Cl. Regulator Valve and Spring Models
IMPORTANT: USE ONLY THE CONV. CL. REGULATOR VALVE FROM THE PACKAGE.
Parts are currently available from GMSPO.
General Motors bulletins are intended for use by professional technicians, not a "do-it-yourselfer". They are written to inform those technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions and know-how to do a job properly and safely. If a condition is described, do not assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See a General Motors dealer servicing your brand of General Motors vehicle for information on whether your vehicle may benefit from the information.
THM 440-T4/HYDRA-MATIC 4T60 REPAIR GUIDELINES #90-7-4 - (08/18/1989)
Models Affected: 1984-90 ALL MODELS WITH 4T60 (440-T4) TRANSMISSIONS
This article is intended to give you some guidelines for inspection and repair of THM 440-T4/Hydra-matic 4T60 transaxles. We will look at areas of concern and related Dealer Technical Bulletins. We will discuss those bulletins and help you decide when the repairs in those bulletins should be used. Generally a bulletin repair would be used when the bulletin refers to a specific complaint the owner may have, or if you find specific damage or wear noted in a bulletin. Don't assume that any 'update' talked about in a bulletin should be done to every transaxle you repair unless it specifically indicates such.
The most important step in any repair is verifying the owner'* concern. If at all possible, the car should be test driven and the exact condition experienced. This will be valuable information when you are looking at those parts spread out on the bench and determining the cause of the condition.
Let'* assume you have verified the condition, determined during the test drive what the cause may be and that you will need to remove the transaxle from the vehicle. As the transaxle is disassembled, there will be some things you will want to inspect while determining what repairs the transaxle might need that may not be listed in the Chassis Service Manual.
BOTTOM PAN, FILTER, ACCUMULATORS, GOVERNOR CIRCUIT, 1-2 SERVO PIPES
Look inside the bottom pan. You may have already had this pan off when the transaxle was in the car, but look for signs of more than a normal amount of material in the bottom of the pan or on the magnet. Pay attention to the type of material it might be. Is it clutch fiber material, steel, brass or aluminum particles? This information will help determine where worn or damaged parts may be as you go through the transaxle.
Sometimes it may be a good idea to open up the filter and look inside. If you have a shift complaint which could be due to sticking valves or if you suspect a torque converter problem, look for clutch plate fiber material inside the filter. If you see this but find no damaged clutch plates or bands anywhere in the transaxle, the fiber material probably came from the torque converter clutch damper plate. The head of a rivet in the damper plate may have broken off and sheared off the clutch plate material. You wouldn't see this by looking into the torque converter. Metal particles originating from a torque converter can also be found in the filter. The filter can give you some good clues.
Late shift complaints could be caused by foreign material stuck in the governor check ball seats limiting governor pressure. Check the governor check balls for leaking seats by positioning the weights so the balls are seated and filling the shaft with solvent. The solvent should not leak from the check balls. Check all four accumulator piston seals for being cut, nicked, rolled or split. Also check the outside edge which seals against the accumulator bore. If it appears shiny, compare the thickness of the old seal with a new seal. If the seal has lost a large amount of material, the bore of the accumulator may be too smooth to hold oil. This will cause the seal to run dry and wear down. Replace the seal and to prevent this from wearing the new seal, scuff up the bore of the accumulator in a horizontal cross-hatch pattern with a fine "abrasive" screen (such as Scotch Brite or an equivalent) and ATF.
PUMP AND VALVE BODY
Take a look at the pump drive shaft bearing surface. If there is any scoring, spalling, or excessive wear on the bearing surface, the pump shaft and bearing should be replaced.
Shift complaints can be caused by a valve sticking in its bore. Do not use sand paper or emery cloth to clean a sticking valve. This can result in the sharp edges being rounded off of the valves. Those sharp edges need to be there to keep the valve and bore clean by scraping out debris.
Clean a sticky valve and its bore by coating the valve with an ultra fine lapping compound or a polishing compound (900 grit or finer) and working the valve in and out of the bore. Be very careful to clean all of the compound out of the bore and off the valve afterwards to avoid sticking or wear in the bore. When clean, the valve should move through the bore by its own weight with out any springs in place.
DRIVEN SPROCKET SUPPORT - 2ND CLUTCH DRUM
Inspect the oil seal rings for the 2nd clutch drum. If this is a 1986 or earlier transaxle equipped with cast iron seal rings, the outside surface of the rings will usually be shiny indicating wear. Look at the inside diameter of the 2nd clutch drum (Figure 1). If there are no grooves worn into the drum where the rings ride, then the drum can be reused and new cast iron seal rings installed. If there are grooves worn into the drum, then refer to Dealer Technical Bulletin 86-7-50. That bulletin will give you information on a new driven sprocket support and Vespel oil seals which should be used along with a new 2nd clutch drum.
INPUT SHAFT AND HOUSING - THIRD CLUTCH INNER PISTON SEAL
A long or delayed 2-3 shift or a burned 3rd clutch could be caused by a damaged or rolled 3rd clutch inner piston seal. Dealer Technical Bulletin 87-7-32 discusses a new wider seal that is now found in seal and gasket kits as well as overhaul kits. The bulletin also describes a kit which includes the new seal, an input shaft and housing assembly, and a 3rd roller clutch. The new seal can be used in the original type input shaft and housing with the stepped groove (Figure 2), if the shaft and housing are not damaged. If shaft and housing or the 3rd roller clutch is damaged, then the kit should be used.
INPUT SPRAG
A condition of intermittent no drive and reverse may be caused by the input sprag assembly. Dealer Technical Bulletin 86-7-53 discusses a first and second type input sprag and their differences. The most significant difference is the width. The second type sprag is wider than the first. If you are working on a 440-T4 built prior to April 1, 1986 which has a first type sprag and you have the transaxle apart as far as the input sprag, you should replace it with a new first type sprag. The first type sprag you get from G.M.*.P.O. has durability improvements. You do not need to update to a second type sprag unless the input carrier is damaged. If it is, the only new carrier available is the one used with the second type sprag. In this case the update kit listed in 86-7-53 would be the best repair.
TRANSAXLE COOLER FLUSHING
It is very important to flush the cooler any time a transaxle is removed for repair. This would include a torque converter replacement. It is also important to flush the cooler if the pump or valve body is removed with the transaxle in the car. Use the Kent-Moore cooler flushing tool J35944 and Biodegradable Flushing Solution. And don't forget to do a cooler flow test as it is described in Dealer Technical Bulletin 87-7-1. Without the proper volume of fluid (2 quarts in 30 seconds) flowing through the cooler and lines, there will not be enough cooling and lubrication capacity for the transaxle. This of course could lead to another breakdown, unnecessary work for you, and most importantly an unsatisfied customer.
Remember to use the 440-T4/Hydra-Matic 4T60 bulletins with the following rule in mind. Unless you have the condition or damage noted in a bulletin, you do not usually need to do the repairs or install the parts listed in that bulletin.
General Motors bulletins are intended for use by professional technicians, not a "do-it-yourselfer". They are written to inform those technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions and know-how to do a job properly and safely. If a condition is described, do not assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See a General Motors dealer servicing your brand of General Motors vehicle for information on whether your vehicle may benefit from the information.
Models Affected: 1984-1990 6000, BONNEVILLE AND GRAND PRIX MODELS WITH 440-T4/4T60
Second clutch diagnosis tips - all 1984-90 Hydra-matic 4T60 (THM 440-T4) transaxles.
A worn or damaged second clutch in a Hydra-matic 4T60 transaxle may exhibit one of the following conditions.
1. Slips or shudders during 1-2 shift
2. Slips in second gear
3. No second gear
When diagnosing a transaxle for one of the above conditions, the following items should be checked first.
1. Test drive the vehicle to verify the condition.
2. Verify proper fluid level.
3. Verify proper transmission line pressure according to the chassis service manual procedure. Check minimum pressure by applying 18" of vacuum to the vacuum modulator (use a hand vacuum pump). Check maximum line pressure with no vacuum applied to the vacuum modulator (vacuum line disconnected). Check both minimum and maximum at 1250 RPM in each range. If there is no boost in pressure with zero vacuum, check for an inoperative vacuum modulator or modulator valve. A ruptured aneroid bellows in a vacuum modulator will result in no boost in pressure with zero vacuum applied.
Note: Do not measure maximum pressure by pulling out on the T.V. cable. 1987 and later models will give you a boosted pressure at full T.V. which is not the same as the maximum pressure reading with zero vacuum. Using the T.V. cable can give you a false maximum pressure reading and will not reveal an inoperative vacuum modulator.
4. Use a vacuum gage on the vacuum line at the vacuum modulator end to verify full engine vacuum is available at the vacuum modulator. The vacuum should register immediately as the engine is started and should respond quickly to engine load changes. When you flash the throttle from idle, the vacuum gage should drop instantly and recover as soon as the engine returns to idle. If the response is slow, check for a restriction in the vacuum line. This restriction can trap vacuum in the modulator on acceleration and cause a slip during shifts because of low boost pressures.
Remember that 1989 and 1990 Grand Prix models with 3.1L engines have a .031" orifice in the modulator end of the line. Do not enlarge or remove this orifice.
Knowing the results of the above checks will help determine the causes of a damaged second clutch once you get inside the transaxle. The second clutch is applied and carrying torque in 2nd, 3rd and 4th gear. Therefore, if fluid level or pressure is low or if the pressure does not boost when the engine is loaded, the 2nd clutch will be one of the first to slip and eventually wear or burn.
Once inside the transaxle there are several items to look for when diagnosing a damaged 2nd clutch:
1. Mispositioned 2nd clutch snap ring.
2. Split, cut or rolled 2nd clutch piston seals or damaged piston.
3. 2nd clutch housing leaking through cracks in the housing or welds.
4. Fluid leaks through 2nd clutch housing check ball or its retainer.
5. Check for deformed or damaged piston return springs in the apply ring and return spring assembly. If these springs are weak, they can allow the 2nd clutch plates to drag while the 2nd clutch is released in 1st and reverse, This can result in premature wear of the 2nd clutch plates.
Note: The piston return springs are easy to overlook but can definitely be a cause of repeat failure of the 2nd clutch.
5. 1984-1986 - driven sprocket support cast iron seals worn or broken. Check for grooves being cut into the inside diameter of the 2nd clutch drum. If so, replace the second clutch drum and install a driven sprocket support with the later style support using Vespel ring seals. 1987-1990 - driven sprocket support Vespel ring seals cracked or broken. Check for damaged or mispositioned four lobe support seals under the Vespel rings.
6. Check the 2nd clutch apply passage which between the driven sprocket support and bushing. Look for the bushing being out of position or worn. If either condition is found, the driven sprocket support should be replaced. Blow air through the passage to check for restrictions or foreign material. If full apply pressure cannot get through to the clutch, it will slip and wear.
7. Check for a leak at the sealing surface where the driven sprocket support contacts the channel plate.
General Motors bulletins are intended for use by professional technicians, not a "do-it-yourselfer". They are written to inform those technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions and know-how to do a job properly and safely. If a condition is described, do not assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See a General Motors dealer servicing your brand of General Motors vehicle for information on whether your vehicle may benefit from the information.
NO 3RD GEAR AND/OR NO DRIVE OR REVERSE #91-7-13 - (10/08/1990)
Subject: NO 3RD GEAR, AND/OR NO DRIVE OR REVERSE CENTER GEARBOX DISTRESS DIAGNOSIS TIPS
Models Affected: 1984-91 6000, BONNEVILLE, GRAND PRIX MODELS WITH 4T60 TRANSMISSIONS
BULLETIN COVERS:
Center gearbox distress diagnosis tips - all 1984-91 HYDRA-MATIC 4T60 transaxles. Center gearbox distress in a HYDRA-MATIC 4T60 transaxle may result in one of the following conditions:
1. No 3rd gear due to a distressed 3rd roller clutch cage. Also, slips in 3rd gear or no 3rd gear.
2. No drive or reverse due to a distressed input sprag.
3. Distressed 3rd and input clutch fiber and reaction (steel) plates.
Many changes were implemented to help reduce center gearbox distress. This bulletin will discuss them and reference bulletins already published on previous changes and what components should be inspected during an overhaul. Also, some other helpful tips and information about lubrication flow have been added. Reference Figures 1 and 2.
Several aftermarket publications have been written concerning different ways to modify the center gear box. Some of the modifications include grinding slots, lining up the lube holes differently, and greatly increasing the fluid level. DO NOT ATTEMPT THESE PROCEDURES! These publications were written to supposedly improve the performance of the center gear box, but instead the modifications can cause durability concerns or the procedures are not necessary.
1. Changes have been made to the 3rd roller clutch which will improve its durability. Revisions have been made to the lube holes on the outside race. Four of the lube holes have been eliminated. When the lube holes are eliminated, the the rollers are less likely to **** or skew when overrunning. When the rollers **** or skew, excessive heat is created. Reference Pontiac Service Bulletin 90-7-35 issued 4/90.
1A. To increase the lubrication to the 3rd roller clutch assembly, a 3rd roller clutch dam was added and the input housing shaft I.D. 4th clutch shaft seal was eliminated. This change occurred for the 1985-1/2 model year. Reference pages 1-7 and 1-8 in the Hydra- matic 440-T4 Product Update book.
2. New Output Shaft With A Single Path Bearing: The new output shaft and bearing allows more lubrication fluid to flow to the center of the gearbox. Reference Pontiac Service Bulletin 90-7-35 issued 4/90.
3. New 10 Plate 3rd Clutch Assembly For SOP 1989: The 10 plate clutch assembly, compared to the previous 8 plate clutch assembly, is for higher torque engine applications and also helps eliminate heat build-up due to numerous repeat manual Lo engagements at speeds around 35 MPH. Reference Pontiac Service Bulletin 89-7-2 issued 10/88.
4. End Plays: If the final drive has too much clearance, this will allow the final drive sun gear to move away from the thrust bearing in the final drive. This will allow too much lube fluid to leak out from the final drive sun gear shaft - with the correct final drive end play, the sun gear would block most of the lube fluid from escaping from the sun gear shaft. If the input housing has too much clearance, this would allow too much lubrication fluid to leak out between the input housing thrust bearing and 3rd roller clutch cam. Some leakage is designed in, but too much due to worn, damaged, missing bushings, too much end play or in- correctly installed parts could cause a durability concern. Reference the lubrication circuit fluid flow description, Figure 1.
5. The final drive sun gear lube groove must face towards the parking gear to allow adequate lubrication flow to the final drive pinions. The final drive sun gear shaft has lubrication holes in the shaft that feed fluid into the step in the sun gear, then through the two slots in the parking gear to the final drive pinions - if the final drive sun gear was installed backwards, the holes in the final drive sun gear shaft would be blocked, not allowing fluid to lubricate the final drive pinions.
6. Check lube pipes for correct installation and any damage (plastic cracked, pipes bent, etc.). Ensure the lube pipe retainer is in the proper position. A mispositioned or damaged component will leak lubrication fluid into the bottom pan instead of directing the fluid to the center of the gearbox. While bolting down the accumulator cover, inspect the position of the lube oil pipe retainer. (Reposition if cocked).
7. Fluid Foaming Due To Overfilling Or Incorrect Thermo Element Height: If the fluid level is too high, the moving parts will churn the fluid, causing the oil to foam. This will cause many durability concerns including damage to the center of the gearbox. An incorrect thermo element height will cause the fluid level to be inaccurate (either too low or too high) when the fluid is up to operating temperatures. Too low a fluid level will cause air to be sucked into the filter, and too high a level will cause fluid foaming due to churning. Check the height with thermo element height setting tool, J 34094-A.
8. 4th clutch hub and shaft assembly should have one needle missing from the inside of the bearing cage for oil flow to the 4th clutch fiber and reaction plates.
9. Cooler Flow Test - Oil cooler for the transaxle that is located in the radiator and the oil-to-air cooler (optional) that is connected in series with the radiator transaxle oil cooler: Correct flow is two quarts of fluid per 30 seconds. Also, it must be flushed; refer to Labor Time Guide for labor operations that must have the transaxle oil cooler flushed.
10. Input Housing To 3rd Roller Cam Thrust Washer Replaced With A Needle Bearing: Reference Pontiac Service Bulletin 86-7-53 issued 2/88 for details about interchangeability and past model service.
11. The lube dam must be installed on most 1986 and newer models between the input and reaction carriers. Leaving a worn, damaged or missing lube dam will allow too much lubrication fluid to leak into the bottom pan. Reference Pontiac Service Bulletin 86-7-23 issued 2/88.
IMPORTANT:
When reassembling a 3rd roller clutch, ensure that the lube dam is pressed into the proper depth. If the 3rd roller clutch is mated to the thrust needle bearing instead of the washer, then:
- press the dam to a depth of 20.72/20.92mm (0.816/0.824") as measured from the bottom side (sprag side) of the outside race to the wide flat edge of the dam as shown in Figure 3.
If using the thrust washer, press the dam (on models so equipped) to a depth of 20.04/20.12mm (0.789/0.792") as measured from the bottom side (sprag side) of the outside race to the wide flat edge of the dam as shown in Figure 3.
NOTICE: Measure the press in depth for the dam as shown in Figure 3. Measuring from the top of the 3rd roller clutch race to the dam will be inaccurate because all the machining of the 3rd roller clutch race is based on the opposite side (side that mates to the input sprag) . If the dam is pressed in too far or not far enough, it could rub on the 3rd roller clutch cage or the snap ring that retains the 3rd clutch return spring and create excess heat to distress the cage of the 3rd roller clutch.
12. Line Pressures: Lubrication fluid is proportional with line pressures. If the line pressure is below specification, then lubrication fluid flow would be inadequate. Check the line pressure as outlined in the service manual and reference Pontiac Service Bulletin 90-7-36 issued 6/90 for further details about vacuum modulator diagnosis.
13. Check converter clutch regulator valve for proper operation, binding, sediment or damage, etc. This valve controls the flow of lubrication - when the torque/viscous converter clutch (TCC/VCC) is applied, mainline lubrication fluid from the pump pressure regulator is routed past the torque converter directly to the cooler; when TCC/VCC is not applied, the fluid is routed through the converter, then to the cooler. If the valve is damaged, a new valve is included in service package 8646934 - use only the convertor clutch regulator valve from this package.
SERVICE PARTS INFORMATION:
Part Number Description Usage
8646934 Package, V.B. Spacer Plate Conv. All 1984-1991 4T60 Cl. Regulator Valve and Spring Models
IMPORTANT: USE ONLY THE CONV. CL. REGULATOR VALVE FROM THE PACKAGE.
Parts are currently available from GMSPO.
General Motors bulletins are intended for use by professional technicians, not a "do-it-yourselfer". They are written to inform those technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions and know-how to do a job properly and safely. If a condition is described, do not assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See a General Motors dealer servicing your brand of General Motors vehicle for information on whether your vehicle may benefit from the information.
THM 440-T4/HYDRA-MATIC 4T60 REPAIR GUIDELINES #90-7-4 - (08/18/1989)
Models Affected: 1984-90 ALL MODELS WITH 4T60 (440-T4) TRANSMISSIONS
This article is intended to give you some guidelines for inspection and repair of THM 440-T4/Hydra-matic 4T60 transaxles. We will look at areas of concern and related Dealer Technical Bulletins. We will discuss those bulletins and help you decide when the repairs in those bulletins should be used. Generally a bulletin repair would be used when the bulletin refers to a specific complaint the owner may have, or if you find specific damage or wear noted in a bulletin. Don't assume that any 'update' talked about in a bulletin should be done to every transaxle you repair unless it specifically indicates such.
The most important step in any repair is verifying the owner'* concern. If at all possible, the car should be test driven and the exact condition experienced. This will be valuable information when you are looking at those parts spread out on the bench and determining the cause of the condition.
Let'* assume you have verified the condition, determined during the test drive what the cause may be and that you will need to remove the transaxle from the vehicle. As the transaxle is disassembled, there will be some things you will want to inspect while determining what repairs the transaxle might need that may not be listed in the Chassis Service Manual.
BOTTOM PAN, FILTER, ACCUMULATORS, GOVERNOR CIRCUIT, 1-2 SERVO PIPES
Look inside the bottom pan. You may have already had this pan off when the transaxle was in the car, but look for signs of more than a normal amount of material in the bottom of the pan or on the magnet. Pay attention to the type of material it might be. Is it clutch fiber material, steel, brass or aluminum particles? This information will help determine where worn or damaged parts may be as you go through the transaxle.
Sometimes it may be a good idea to open up the filter and look inside. If you have a shift complaint which could be due to sticking valves or if you suspect a torque converter problem, look for clutch plate fiber material inside the filter. If you see this but find no damaged clutch plates or bands anywhere in the transaxle, the fiber material probably came from the torque converter clutch damper plate. The head of a rivet in the damper plate may have broken off and sheared off the clutch plate material. You wouldn't see this by looking into the torque converter. Metal particles originating from a torque converter can also be found in the filter. The filter can give you some good clues.
Late shift complaints could be caused by foreign material stuck in the governor check ball seats limiting governor pressure. Check the governor check balls for leaking seats by positioning the weights so the balls are seated and filling the shaft with solvent. The solvent should not leak from the check balls. Check all four accumulator piston seals for being cut, nicked, rolled or split. Also check the outside edge which seals against the accumulator bore. If it appears shiny, compare the thickness of the old seal with a new seal. If the seal has lost a large amount of material, the bore of the accumulator may be too smooth to hold oil. This will cause the seal to run dry and wear down. Replace the seal and to prevent this from wearing the new seal, scuff up the bore of the accumulator in a horizontal cross-hatch pattern with a fine "abrasive" screen (such as Scotch Brite or an equivalent) and ATF.
PUMP AND VALVE BODY
Take a look at the pump drive shaft bearing surface. If there is any scoring, spalling, or excessive wear on the bearing surface, the pump shaft and bearing should be replaced.
Shift complaints can be caused by a valve sticking in its bore. Do not use sand paper or emery cloth to clean a sticking valve. This can result in the sharp edges being rounded off of the valves. Those sharp edges need to be there to keep the valve and bore clean by scraping out debris.
Clean a sticky valve and its bore by coating the valve with an ultra fine lapping compound or a polishing compound (900 grit or finer) and working the valve in and out of the bore. Be very careful to clean all of the compound out of the bore and off the valve afterwards to avoid sticking or wear in the bore. When clean, the valve should move through the bore by its own weight with out any springs in place.
DRIVEN SPROCKET SUPPORT - 2ND CLUTCH DRUM
Inspect the oil seal rings for the 2nd clutch drum. If this is a 1986 or earlier transaxle equipped with cast iron seal rings, the outside surface of the rings will usually be shiny indicating wear. Look at the inside diameter of the 2nd clutch drum (Figure 1). If there are no grooves worn into the drum where the rings ride, then the drum can be reused and new cast iron seal rings installed. If there are grooves worn into the drum, then refer to Dealer Technical Bulletin 86-7-50. That bulletin will give you information on a new driven sprocket support and Vespel oil seals which should be used along with a new 2nd clutch drum.
INPUT SHAFT AND HOUSING - THIRD CLUTCH INNER PISTON SEAL
A long or delayed 2-3 shift or a burned 3rd clutch could be caused by a damaged or rolled 3rd clutch inner piston seal. Dealer Technical Bulletin 87-7-32 discusses a new wider seal that is now found in seal and gasket kits as well as overhaul kits. The bulletin also describes a kit which includes the new seal, an input shaft and housing assembly, and a 3rd roller clutch. The new seal can be used in the original type input shaft and housing with the stepped groove (Figure 2), if the shaft and housing are not damaged. If shaft and housing or the 3rd roller clutch is damaged, then the kit should be used.
INPUT SPRAG
A condition of intermittent no drive and reverse may be caused by the input sprag assembly. Dealer Technical Bulletin 86-7-53 discusses a first and second type input sprag and their differences. The most significant difference is the width. The second type sprag is wider than the first. If you are working on a 440-T4 built prior to April 1, 1986 which has a first type sprag and you have the transaxle apart as far as the input sprag, you should replace it with a new first type sprag. The first type sprag you get from G.M.*.P.O. has durability improvements. You do not need to update to a second type sprag unless the input carrier is damaged. If it is, the only new carrier available is the one used with the second type sprag. In this case the update kit listed in 86-7-53 would be the best repair.
TRANSAXLE COOLER FLUSHING
It is very important to flush the cooler any time a transaxle is removed for repair. This would include a torque converter replacement. It is also important to flush the cooler if the pump or valve body is removed with the transaxle in the car. Use the Kent-Moore cooler flushing tool J35944 and Biodegradable Flushing Solution. And don't forget to do a cooler flow test as it is described in Dealer Technical Bulletin 87-7-1. Without the proper volume of fluid (2 quarts in 30 seconds) flowing through the cooler and lines, there will not be enough cooling and lubrication capacity for the transaxle. This of course could lead to another breakdown, unnecessary work for you, and most importantly an unsatisfied customer.
Remember to use the 440-T4/Hydra-Matic 4T60 bulletins with the following rule in mind. Unless you have the condition or damage noted in a bulletin, you do not usually need to do the repairs or install the parts listed in that bulletin.
General Motors bulletins are intended for use by professional technicians, not a "do-it-yourselfer". They are written to inform those technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions and know-how to do a job properly and safely. If a condition is described, do not assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See a General Motors dealer servicing your brand of General Motors vehicle for information on whether your vehicle may benefit from the information.
01-26-2004, 08:51 PM
#6
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No true 4th gear? Mine used to seem to have a third and fourth gear, but when accelerating to highway speeds, 3rd seems MIA. Then it goes into fourth (positive feeling shift), then TCC locks up. At city speeds, 3rd has a lot of shake during medium throttle.
01-29-2004, 08:25 AM
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Originally Posted by jwikoff99
No true 4th gear? Mine used to seem to have a third and fourth gear, but when accelerating to highway speeds, 3rd seems MIA. Then it goes into fourth (positive feeling shift), then TCC locks up. At city speeds, 3rd has a lot of shake during medium throttle.
