I have a 97 audi a4 1.8t. with trans problem.

couple of things to try first , is the trans fluid at correct level ? when was the fluid last replaced ? have the OBD codes read as may tell you what the problem is , if you done all this i'd go to a repar shop for advice

Check the Coolant (antifreeze) level. My 94 continental has a hard time shifting from 2nd to 3rd when the level is low. Also, this may indicate that the transmission fluid is too old to work properly. The transmission fluid is cooled at the bottom of the radiator, since cool fluid works better than hot fluid (especially when the trans fluid is old) that could make the transmission not shift properly. Keep the coolant level up until you can have the trans fluid checked.

It could possibly be a bad electrical connection or poor connection with the transmission. Did the mechanic get any error codes?

then the problem will be in the wiring harness and connections

CHANGE FILTER IN TRAN

down the dipstick tube!!!(really)DO NOT OVERFILL...
Your audi is fitted with a fuzzy logic gearbox, it will change according to your driving style.TRY THIS,put into 1st and without touching gas pedal, let the car accelerate to top gear,stop Then using onle 1/3rd gas pedal do it again.then using 2/3rds do it again.then only using the minimum pedal req accelerate to max legal limit.(try not to use brake pedal,let the car slow down itself,until you have to)then drive as normal, it will feel like a different car.

you may not have trans problem at all. most of the time your motor mounts when worn out or broken can cause a hard ****. Put your car into gear with your foot on the brake and give some gas abrubtly and see if your engine jumps. do the same in reverse. remember to use the brake and have your hood open to see if your motor jumps.

i had a problem similar 2 this..i thought i threw out my passing gear and well my trans period i took it over to my uncles shop and it was just a fuse that went out. look at your fuse panel it should be like Automatic or auto shift. try that bro.

It has nothing to do with the transmission, it's your engine mount thats bad.