Yep, another tranny problem thread
03-09-2007, 11:24 AM
#21
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anyone ever have that song with the lyrics "Another one bites the dust another one bites the dust And another one gone, and another one gone another one bites the dust" come into mind when crap breaks or is it just me? 
03-09-2007, 02:40 PM
#22
Talked with Chuck. I'm going to drop the pan. Have a look at the fluid and in the pan. Pull the 4th gear servo see if any of the seals on it are pinched. Since 2nd gear is still strong, 2nd and 4th use the same band, might be the servo.
03-10-2007, 09:34 AM
#24
Pan is off and nothing looks out of place. Fluid is fine. Completely normal I would say. I don't see getting the servo out with it in the truck. The stocker was a PITA and the Sonnax unit is probably 1/2" longer. 
Only thing I am curious about is this component. It is just laying in there. Connected to nothing but the wiring harness. I don't remember seeing this in my previous pulldowns for shift kit.
Only thing I am curious about is this component. It is just laying in there. Connected to nothing but the wiring harness. I don't remember seeing this in my previous pulldowns for shift kit.
03-10-2007, 03:16 PM
#25
Put it all back together and went for a drive. Took along the laptop and played with the transmission settings via HPT. Now I don't know what the heck is going on.
In 4th forced and TCC forced locked it will not slip. It still will in 4th with it unlocked but not to the level it did last night. Feels like it has a 5000 rpm stall converter in it but not evident 1st thru 3rd. Weird.
It has something to do with PWM. I forced PWM off and it behaves like it did in 4th in all gears so it might be the Torque converter or in the tune. Played with different levels of PWM Maybe the clutch has worn some and now is slipping? Wouldn't it slip in all gears if it were the converter? I thought PWM was only a control for how much fluid pressure was applied to the clutch and not effect the converter behavior when the clutch wasn't locked? I guess I don't understand how the Converter, TCC, PWM and tranny work. Time for a lot of research.
In 4th forced and TCC forced locked it will not slip. It still will in 4th with it unlocked but not to the level it did last night. Feels like it has a 5000 rpm stall converter in it but not evident 1st thru 3rd. Weird.
It has something to do with PWM. I forced PWM off and it behaves like it did in 4th in all gears so it might be the Torque converter or in the tune. Played with different levels of PWM Maybe the clutch has worn some and now is slipping? Wouldn't it slip in all gears if it were the converter? I thought PWM was only a control for how much fluid pressure was applied to the clutch and not effect the converter behavior when the clutch wasn't locked? I guess I don't understand how the Converter, TCC, PWM and tranny work. Time for a lot of research.
Last edited by KySilverado; 03-10-2007 at 08:36 PM.
03-10-2007, 04:07 PM
#26
Originally Posted by LBSBLOWN
So yo don't have this table or your not using it?
TCC DUTY CYCLE MINIMUM.
TCC DUTY CYCLE MINIMUM.
03-10-2007, 04:34 PM
#27
The thing with the arrow pointed to it is the presure control solenoid. You mentioned that your transmission is vacuum modulated, so that solenoid isn't needed. If you remove it you'll get a SES code. That can be programmed out.
It is weird that only fourth gear is affected. Fourth gear uses the same friction materials as second and third gear combined.
It is weird that only fourth gear is affected. Fourth gear uses the same friction materials as second and third gear combined.
03-10-2007, 08:54 PM
#28
Originally Posted by James B.
The thing with the arrow pointed to it is the presure control solenoid. You mentioned that your transmission is vacuum modulated, so that solenoid isn't needed. If you remove it you'll get a SES code. That can be programmed out.
It is weird that only fourth gear is affected. Fourth gear uses the same friction materials as second and third gear combined.
It is weird that only fourth gear is affected. Fourth gear uses the same friction materials as second and third gear combined.
I wish I knew more about transmissions. All I know are the symptoms. 4th slip under high torque, TCC unlocked. Building a little more heat cruising around town than it has been. Maybe 20*, cools back down out on the highway cruising with the TC locked. Beginning to think it is the TC.
03-10-2007, 10:36 PM
#29
Maybe the vacuum modulator has failed and it's not commanding enough line pressure to hold fourth. Fourth gear with TCC lockup needs more combined fluid volume than any other combination of gear and lockup since you have four different pistons applied.