[MARAUDER2003]

Hi
Does anybody know what the following problem is. Recently I have had to go into work very early in the morning. It has been cold the last few days in AZ. My transmission acts weird when it’s cold (I hadn’t noticed this behavior since I work afternoon/evenings and rarely up in the mornings). Basically, it does what some people consider a bump shift but it’s more than that. It does not want to downshift in a normal way, it does AFTER a few seconds coming to a stop, with some RPM surge too. I have to keep my foot on the brake pedal firmly to make sure it remains at a stop and doesn’t lurch forward. If I let it warm up sufficiently, it does not do this. I’ve been trying to duplicate the issue in normal weather and I have made it do it a couple of times after aggressive driving/shifting when coming to a stop. It doesn’t do it if I drive in warm weather and in a normal driving way. The problem is at downshifting, when it needs to go from a higher gear to a stop in a hurry, it almost seems like something latches on, and it does not want to release in time. It upshifts perfectly. I had a drop service with genuine ATF+4 done like 6k miles ago and this is not the original tranny (replaced it like 3+ years ago and it has around 140k+ miles). No other symptoms, no codes. 02 2.7L Intrepid SE. Any ideas? Is my transmission showing signs that it’s in the way out?
Thanks!

 

[peva]

Random thoughts:
• Are you 100% sure they put in ATF+4?
• Verify correct fluid level.
• Try removing battery power for 20+ minutes (disconnect the top cable from the negative jump post) to reset the PCM to factory presets, and it will adapt to the car and your driving habits over time - this may or may not fix the problem.
• When replacing fluid, because the properties of the fluid change as it wears and ages so fresh new fluid is a sudden change of fluid properties, you're supposed to have the dealer put it thru a calibration cycle to optimize the CVIs (clutch volume indexes) to provide smooth shifts. I don't remember if CVIs are fixed (locked) once calibrated or if they also are able to adapt themselves over time. My guess is that they automatically adapt, in which case a forced re-cal shouldn't be necessary unless you want optimized behavior right out the gate.
• There may be something going on with the torque converter or its lockup clutch or something (I'm nowhere near an expert on such things - I just think I remember them being mentioned in past discussions of similar problems.)

Dan (Daytrepper) is the real expert on transmission problems like this. You might try PM'ing him if he doesn't pop into this thread.

 

[Ronbo]

I thought CVI= Clutch Volume Index?

 

[peva]

I thought CVI= Clutch Volume Index?

And you thought right. (I just edited my post.)

 

[MARAUDER2003]

Random thoughts:
• Are you 100% sure they put in ATF+4?
• Verify correct fluid level.
• Try removing battery power for 20+ minutes (disconnect the top cable from the negative jump post) to reset the PCM to factory presets, and it will adapt to the car and your driving habits over time - this may or may not fix the problem.
• When replacing fluid, because the properties of the fluid change as it wears and ages so fresh new fluid is a sudden change of fluid properties, you're supposed to have the dealer put it thru a calibration cycle to optimize the CVIs (clutch volume indexes) to provide smooth shifts. I don't remember if CVIs are fixed (locked) once calibrated or if they also are able to adapt themselves over time. My guess is that they automatically adapt, in which case a forced re-cal shouldn't be necessary unless you want optimized behavior right out the gate.
• There may be something going on with the torque converter or its lockup clutch or something (I'm nowhere near an expert on such things - I just think I remember them being mentioned in past discussions of similar problems.)

Dan (Daytrepper) is the real expert on transmission problems like this. You might try PM'ing him if he doesn't pop into this thread.

Yes, 100% ATF+4 from wmart.
Correct fluid level.
I did disconnect the battery to reset the PCM. I did that several times. It didn't solve the problem.
I wouldn't know what the CVIs values are.
I'm inclined to think that there is a problem with the torque converter like you state. But like you say, i'm not an expert in these matters either.
The only good thing is that the problem is when it's cold. It doesn't do it when the weather is warm and I drive normal unless I drive very aggressively.
i'd be very interested to see what other people have to say.

 

[Ronbo]

And you thought right. (I just edited my post.)

Just sayin' !

 

[AustinM]

. It does not want to downshift in a normal way, it does AFTER a few seconds coming to a stop, with some RPM surge too. I have to keep my foot on the brake pedal firmly to make sure it remains at a stop and doesn’t lurch forward.


My thought, its not a tranny problem but rather an engine issue. Specifically the throttle body and / or idle air control. If the idle air control is "stuck" then the engine will race when cold or studder when warmed up. (Depends which position it stuck in) Before expensive tranny solutions I'd pull the IAC apart and clean it and make certain its working properly. While you are at it, cleaning the throttle body is easy.