TCC problems?

[chartman]

I have little knowledge about what a TCC's correct operations are. I have a serious driveline shudder when the TCC is locking or locked. When i back off the gas and push it lightly sometimes i can cause the van to shake really bad. Scarry bad. Ive become skilled at ridding out the shutter long enought to tap the brake. It seems when the TCC unlocks the shutter is gone. I read Lockup will bring out driveline problems since its fully locked.

So my main questions.....

1) When in lockup should the TCC slip? I continue to see the TCC slipping a bit even in lockup! I thought at lockup no fluid is passing through the Converter.

2) In lockup i see the TCC duty cycle is pretty high when im on the gas or off the gas.

Thanks!

[lockdoc]

I'll try and and see if I can find more info on your problem but this is what I do know. You have PWM (pulse width modulated) TCC. What that means is that the PWM modulates the pressure to the TCC similar to the ABS on your brakes. It supposed to make the lock and unlock less noticable while driving. You are incorrect about the fluid being cut off from the TC. It actually adds to it in a certain area to lock plates together. Hopes this helps you visualize what is happening.

[brianj]

chartman,

Sorry if this is redundant, but have you checked your cap and rotor? My van had a bad shudder, that I determined was happening only when the tcc locked up. It ended up being ignition related.

My 01 with 60000 miles had a cap that looked like it had been through a couple million miles. It was due to needing the vents poked out of the bottom of the distributor. Thanks to V8famvan, we took care of that!

[Astro95]

TCC should lock up 100%. Usually shudder at lockup indicates a bad torque converter clutch. It's entirely possible that the friction material is burnt.

Unlocking should be unaffected because the TCC is releasing anyway.