Hi there quick questions to see if anyone has gone through this.

I have a 98 auto a4 1.8t quattro sport model. Only mods are GIAC and 3 inch exhaust, drop in air filter.

Long story short mechanic messed up tranny, just got it rebuilt ouch i know.

Now after getting it back i changed the stock 16 inch rims with 17inch replica rsm rims.
This is also during the same time i got the new tranny.

Now shifting is suffering in drive. 3rd to 4th seems like it slips "neutralizes" according to transmission guy. He took it for a drive and said that the car shifts fine in trip no jumps hesitation or anythign, but in drive the boost is almost unpredicatable, either slow like a granny or full throttle almost.

I was wondering if anyone would know why its boosting wierd? can the larger rims affect it.

I have never seen this before but even the turbo is glowing after a good run.

 

Whatever is causing it, it's not the wheels. The problem with having the transmission guy test it out is, of course he's going to tell you it's fine. If it isn't, he's gonna have to cover the repair. You need to take him out with you on a drive, with you driving, and show him what it's doing. These cars are very smooth in operation, either in auto or tip mode, and the boost is quick and progressive and very linear. It sounds to me like the issue is the transmission. If it's slipping and not holding in gear, effectively it's removing the load from the engine, and in that case the engine won't build boost (it needs to be loaded to build the boost). If it's slipping and then catching, and the turbo is spooling the whole time, when the gear catches it's going to deliver a wallop of boost, and it won't be boosting while the trans is slipping. This would give you the unpredicability you're talking about. Take him for a ride, show him what you mean, don't buy any bullshit like "well if you drive it hard you can't expect it to be smooth" or anything like that. Make him stand behind his work and get your car in order, and if he balks at that start discussing lawyers and the BBB.

 

hey thanks for the quick reply. also forgot to let you know when shifting into reverse there's a big jolt. Which on a fresh tranny rebuild should be smooth from what i think. For the 3rd to 4th the revs jumps 500rpm before going into fourth gear in trip mode or drive.
You think there is any chance that the n75 valve maybe going bad? Sometimes it seems like the turbo doesn't want to kick in until i give it 50% throttle or more.

After having all the engine parts repaired/replaced its been running really strong but definitely different, something im not use to. The problem is after the engine repairs, i never got to test drive the difference. the engine mechanic messed up the transmission, So when i got the car back it had "new" engine and rebuilt tranny. so i never got to try the engine before the new tranny.
any thoughts would be appreciated.

 

Sounds to me like the engine guy messed up ur trans. Look at what you said in the first paragraph of your last message. "when shifting into reverse there's a big jolt." Big no, no. Cars aren't supposed to "jolt" into gear. If the new trans guy says its the trans, take it back to the engine guy and have him fix it. If they've got a problem with it, tell him that the trans guy sent you. It'll be a long tedious process, but dude, don't get sucked into paying a crap ton of money because someone else messed up on your car. Good luck

 

I was having the same issue with the slipping and boost problem, I had a transmission code pull up on vag com, reset the ecu, then took it to a shop that had vagcom and they had to turn down the boost 1% and the timing was off. Ever since then I have had no slipping and full boost