Park Avenue Ultra Trans Bad???

[brew]

Just got a 95 Buick Park Ave Ultra-Supercharged 3800-very fast. One problem though, the transmission slips.....

With the gear selector in OD it acts like it's in neutral. Then when I give it a little gas, it goes THUNK!, really hard, like a tranny drop, and accelerates.

If I accelerate too hard, it slips and the engine bounces off the rev limiter.

Like I said, I just got this car, I guess the engine was rebuilt about 5K ago, evidenced by the little sticky labels someone put all over the engine bay to remember where things plug back in.

I looked around and found the cruise control connector hanging loose, the inlet air temp sensor disconnected and finally, the vacuum line leading to the modulator valve. Would this have caused the trans to toast?

Now, I understand the modulator controls upshifting. I don't know how, I guess it helps regulate pressure. Maybe someone could clue me in. My concern is this...

Even after I plugged everything back in, the trans still acted the same. Can I get by with simply replacing clutches, a "soft parts" rebuild? Or does something like this end up going deeper? Like torque converter, planetary gears, front pump, etc.?

By the way, already changed the fluid and filter....no change to the way the trans acts. But I did manage to put a neato drain plug on the pan.....

Thanks, Brew

 

[Chris A]

You have a 4t60e in your car. The modulator's sole responsibility is to control shift firmness. The electronics control shiftpoints. Without the line plugged in, it was running at maximum line pressure all the time. I'm not sure why, but it can take out the tranny. Don't know a whole lot more on this subject, ie if it can take out the pump or some of the solenoids because of excessive pressure, or even the pump.