Tranny overdrive Question??? - Page 2 - GM Forum - Buick, Cadillac, Chev, Olds, GMC & Pontiac chat


1992-1999 Series I L27 (1992-1994 SE,SLE, SSE) & Series II L36 (1995-1999 SE, SSE, SLE) and common problems for the Series I and II L67 (all supercharged models 92-99) Including Olds 88's, Olds LSS's and Buick Lesabres Please use General Chat for non-mechanical issues, and Performance and Brainstorming for improvements.

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Old 09-25-2003, 02:08 PM   #11
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I know this is nerve wrecking by now, but I have the problem at 30 mph, 25mph, 40 mph without OD even being thought of yet. Now, is this a tranny issue? Or its still normal
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Old 09-25-2003, 04:07 PM   #12
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It is totally normal for the rpms to fall dramatically when your foot is lifted below ~45mph. Above torque convertor lockup speed(40+ -- dependent on load, throttle position, engine temp, etc.) once the torque convertor has locked up the rpms should hold UNLESS you touch the brake. In fact, that is the best way to test if the lockup is working.

If you're not coasting uphill with vehicle speed rapidly dropping, you shouldn't see significant tach movement above 55 mph when you re-apply the throttle.
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Old 09-25-2003, 05:11 PM   #13
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Quote:
Originally Posted by jr's3800
yeah all of this is normal for the 4T60, 4T60-E, 4T65-E... When you tap the brake pedal, remove your foot from the accellerator, or depress the accelerator to a certain degree the Torque Converter Clutch will dissengage... When you put your foot back on the accelerator, the PCM will see the load factors, and command the TCC to fall into lock up mode... you are still in OverDrive, but the TCC is engaging and disengaging due to various driving conditions... All a normal part of these transmissions...
Don, Thanks for this info. Takes a load off of my mind.
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Old 09-25-2003, 08:52 PM   #14
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Don, I like the new pic in your sig.
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Old 09-25-2003, 09:00 PM   #15
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Outstanding. I like it.
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Old 09-26-2003, 01:12 AM   #16
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if i remember correctly the criteria for TCC engagement is 4%<TPS<50%
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Old 09-26-2003, 03:33 AM   #17
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No problem... A lot of people see this as a problem... But it a normal operating factor of these transmissions.... some of the newer 4T65-E'* have a PWM I think, or Pulse Width Modulator valve, and the PCM will control apply at various percentages, making the application of the converter smoother... In the 4T60-E'* the bonnevilles didn't use the PWM for 92-95.... Not sure about 96-97... I have driven a few cars with the 4T45-E'* and the 4T65-E'*, I like the 4T60-E better as far as how it performs... But the 4T65-E'* apply the converter at varying degrees, allow for lower reves from the engine, and a little better fuel effiency... But for all of the abuse I have given my 4T60-E, all I can say is that its a winner... [/quote]

THanks Don. I see know why the car does it. The simple breakdown of the different trannies these cars have. Now I understand.
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Old 09-26-2003, 04:37 AM   #18
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Quote:
Originally Posted by jr's3800
Quote:
Originally Posted by aviator327
Outstanding. I like it.
On topic.... I think I need to replace my shift accumulators to get some of my smooth shift back.... Either I have killed the accumulators, or they have worn out over time with abuse...

Off topic..... Aviator, I should get a set of those " Bonneville SE " emblems that you have on your doors... That would throw a lot of people off about my car.... I'll have the 92 badges and the 94-95 front grille.... No one will know its a " Series II 3800 "
Don, That sounds like a pretty good idea putting on the SE emblems. I could then bring my car down and park them side by side. That would probably get them to start scratching their heads.
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