Hello, Having the same issue with my 1994 SSEI. It shifts fine thru the 4 gears then when the torque converter locks up it shuders pretty bad and continues to do so until you let off the gas and accelerate again to force it to come out of lock up. as soon as it locks up again though...there is the vibration. Driving to work this morning in the rain it downshifted to 3rd and never went back to 4th and the converter never locked up. Trans fluid is clean and does not smell. From the research i have been doing this is looking more like an electrical issue somewhere. any thoughts ?

Hi,

I moved you to your own thread to get fresh and the latest info. Old threads don't always reflect the most current knowledge aka the stuff you need.

I'm thinking that the trans was hot and went into an overheat protection. Although I'm not 100% sure if your 4T60E transmission has that.

It sounds to me like you have an internal transmission problem and need an overhaul.

An electrical issue will not cause a shudder on TCC apply. That is caused by a hydraulic leak or a bad converter etc.

When was the last time you did a full tuneup? I have seen many times where an issue causes this, and it only surfaces when the drive train is locked together. I find it odd, and scary at the same time, when you mentioned that it shifted to third and held though...