'92 Passat gear shifting problem

[ValMin]

I have this '92 automatic Passat for 2 years now. I had a lot of trouble with it since I bought it, but when I thaught the nightmare ended (rebuilding the transmission) I got a new one. After the engine warms up (above 90 celsius), shifting gears becomes a nightmare: when shifting up from the 3rd to the 4th, it first breaks the car (you feel like somebody is pulling it back) then the forth kiks in (like a kick in the a..).
When shifting backwards (4th to the 3rd), you must be carefull not to fly through the windshield.

I went back to the guy who did the transmission and he said it is fine. He also used the computer and he said it shows no fault ...

Does anybody have any idea what can cause it?

Thanks in advance!

[boschmann]

I've heard the problem often lies in the trans control module or internal wiring of the tranny, a normal rebuilder often doesn't fix it. Try talking to these guys, they're very good with Passat automatics & even live in your area.

http://tech.bentleypublishers.com/forum.jspa?forumID=42

[ValMin]

Thanks, Boschman for the tip. I posted the same question on their site.

I am not sure whether it is related to the above problem or not, but from time to time, when starting up the engine while it is still warm (say after a 10-15 minutes) it starts raving up to 1,500 rpm or even over. If I press the gas pedal few times it will eventually go back to 900 or so. If I don't do that, it keeps it on and breaking becomes hazardous, as it takes longer and more pressure on the break pedal to stop the car.