Help me please! My transmission chatters/vibrates sometimes when shifting to 3rd, with o/d off, also when shifting to o/d. This is mainly at lower speeds and not accelerating hard. Is this the torque converter slipping when it tries to lock up? I have 80,000 miles and have changed the fluid twice and had to reflash the computer once. Also any tips on this tranny will be greatly appreciated.

This may be a repeat, the first one didn't seem to post!

 

Try the APPS reset procedure.