Trans problem
09-15-2007, 11:08 PM
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Trans problem
All of a sudden on the way home from an hours drive, my trans quit going into overdrive.
I notice that now when the shifter is in the OD position and I let off the gas, the RPMs go to idle even if I'm going down a hill and the car is gaining speed. If I shift into D it doesn't free wheel like that at all, the RPM keeps pace with the speed.
Does this mean that a tranny rebuild is in my near future?
Trans oil was changed about 3000 km ago, old oil looked and smelled good, I just changed it because I had no idea when it was done last.
I notice that now when the shifter is in the OD position and I let off the gas, the RPMs go to idle even if I'm going down a hill and the car is gaining speed. If I shift into D it doesn't free wheel like that at all, the RPM keeps pace with the speed.
Does this mean that a tranny rebuild is in my near future?
Trans oil was changed about 3000 km ago, old oil looked and smelled good, I just changed it because I had no idea when it was done last.
09-15-2007, 11:18 PM
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not going into OD is bad...
but freewheeling is normal. OD is designed to save gas...by allowing you to freewheel, the engine lowers RPM, saving fuel...and not slowing you down so you dont have to speed back up. D on the other hand is seen as 3rd gear, it will lock you in and slow you down regardless.
I suggest seafoam trans tune and a full transmission flush and I do believe it will some back to life.
but freewheeling is normal. OD is designed to save gas...by allowing you to freewheel, the engine lowers RPM, saving fuel...and not slowing you down so you dont have to speed back up. D on the other hand is seen as 3rd gear, it will lock you in and slow you down regardless.
I suggest seafoam trans tune and a full transmission flush and I do believe it will some back to life.
09-16-2007, 01:32 AM
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Re: Trans problem
Originally Posted by JMH1950
All of a sudden on the way home from an hours drive, my trans quit going into overdrive.
I notice that now when the shifter is in the OD position and I let off the gas, the RPMs go to idle even if I'm going down a hill and the car is gaining speed. If I shift into D it doesn't free wheel like that at all, the RPM keeps pace with the speed.
Does this mean that a tranny rebuild is in my near future?
Trans oil was changed about 3000 km ago, old oil looked and smelled good, I just changed it because I had no idea when it was done last.
I notice that now when the shifter is in the OD position and I let off the gas, the RPMs go to idle even if I'm going down a hill and the car is gaining speed. If I shift into D it doesn't free wheel like that at all, the RPM keeps pace with the speed.
Does this mean that a tranny rebuild is in my near future?
Trans oil was changed about 3000 km ago, old oil looked and smelled good, I just changed it because I had no idea when it was done last.
Option A:
The trans was overheating and going into protection mode, refusing to let the car into 'TCC lockup' and letting you idle down all the way without the engine matching revs. Check lines for clogs or trans cooler. Check your water temp gauge. If this is showing hotter than normal you could be experiencing your trans overheating.
Option B:
Computer glitch (i have a 94, been through a few of them) causes it to just not like overdrive. Because as soon as you pull over, turn off the car and restart it will shift fine through all gears with no cool down.
Option Y:
Something in the trans screwing up. Im hoping this is NOT the case as its expensive and mine was rebuilt only 39k miles ago.
I am not a mechanic and havent solved my problem yet, but maybe that will give you some ideas.
09-16-2007, 11:08 AM
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I can rule out option A. Temp gauge was right where it always stays 85 C (185 F)
Once I get mobile, I'll check Option B. If it shifts through all the gears, I'll still do the SeaFoam Trans clean and flush just because.
Once I get mobile, I'll check Option B. If it shifts through all the gears, I'll still do the SeaFoam Trans clean and flush just because.
09-16-2007, 12:47 PM
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it certainly can't hurt.
i forgot to say also. run the trans tune through the transmission for a minimum of 30 miles. i've found its quite useless otherwise.
also...your temp gauge is not going to tell you the temp of your trans, you need an auxiliary gauge to tell you that.
i forgot to say also. run the trans tune through the transmission for a minimum of 30 miles. i've found its quite useless otherwise.
also...your temp gauge is not going to tell you the temp of your trans, you need an auxiliary gauge to tell you that.
09-16-2007, 01:47 PM
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Either that or a Scan tool capable of reading the 94-95 Bonneville.. The 94-95 PCM does monitor the tranny temps..
This could be a Temp related issue... Could be a valve body issue... Could be an O Ring issue... Could even be a bad 4th input shaft or fried 4th clutches..
Its hard to say...
You need to see if there are any history codes in that computer that relate to overheating or Tranny slip codes...
Most of these will not set off the SES light
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This could be a Temp related issue... Could be a valve body issue... Could be an O Ring issue... Could even be a bad 4th input shaft or fried 4th clutches..
Its hard to say...
You need to see if there are any history codes in that computer that relate to overheating or Tranny slip codes...
Most of these will not set off the SES light
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09-16-2007, 03:12 PM
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also...your temp gauge is not going to tell you the temp of your trans, you need an auxiliary gauge to tell you that.
Anyway things are back to normal this morning. I'm still going to do a SeaFoam treatment just in case it is something sticking in the trans.
Either that or a Scan tool capable of reading the 94-95 Bonneville.. The 94-95 PCM does monitor the tranny temps..
09-16-2007, 05:08 PM
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Originally Posted by JMH1950
also...your temp gauge is not going to tell you the temp of your trans, you need an auxiliary gauge to tell you that.
09-16-2007, 05:50 PM
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We generally like to see these 4T60-E'* stay under 200F...
260F is not favored by the PCM and it will do what it can to lower the temps or keep the temps from increasing..
Keep in mind here in my Climate it gets pretty warm.. Middle of September and we are still seeing 90F...
In the past with temps as high as 97F I have seen the trans spike to 230F without any abuse..
I was starting to have heat related issues, never lost OD..... But the shifts and TCC apply were getting nasty... I ended up adding a Tranny cooler to help keep the temps down... I generally run between 150-160F on most hot days... If you can keep them cooler to a certain degree you can double the life of the trans..
Also keep in mind that too cold is just as bad as too hot.. You do want the trans to warm up, just don't want it to cook
I do think a Scantool will give you a better idea of what the PCM is trying to do.. You will be able to see the trans temps, Gear the PCM is commanding the Trans to be in via the solenoids.. You will also be able to monitor the TCC Apply and the amount of TCC slip when the TCC is applied
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260F is not favored by the PCM and it will do what it can to lower the temps or keep the temps from increasing..
Keep in mind here in my Climate it gets pretty warm.. Middle of September and we are still seeing 90F...
In the past with temps as high as 97F I have seen the trans spike to 230F without any abuse..
I was starting to have heat related issues, never lost OD..... But the shifts and TCC apply were getting nasty... I ended up adding a Tranny cooler to help keep the temps down... I generally run between 150-160F on most hot days... If you can keep them cooler to a certain degree you can double the life of the trans..
Also keep in mind that too cold is just as bad as too hot.. You do want the trans to warm up, just don't want it to cook
I do think a Scantool will give you a better idea of what the PCM is trying to do.. You will be able to see the trans temps, Gear the PCM is commanding the Trans to be in via the solenoids.. You will also be able to monitor the TCC Apply and the amount of TCC slip when the TCC is applied
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