I have a 99 A4 with 30k miles. I bought the car at 26k miles and have been racing it almost weekly since then. A 3600 vig stall was one of my first mods, along with a shift kit and a trans cooler. The trans fluid was changed at that time too.

I have been getting a strange vibration/grind lately. I have been through enough rears to know that is not the problem, and it seems very highly unlikely that it is an engine problem.

Here's the issue - the 3-4 part throttle shift has been a little strange, it seems like it takes slightly longer than the other shifts, and when it does happen it does this vibration/grind thing as if it's struggling to get into gear. Then it's fine. If I'm going 50-60mph and I apply light throttle (pass someone, like 20-30% pedal) it also does it, the grind/vibration/chug type of thing.

It has no issues under wide open throttle (even 3-4 shift) and drives fine elsewise. It doesn't seem to slip, I'm not sure if the stall would hide that or not.

Anyway I knew this day was coming, and I plan to keep racing and adding more power. I will probably make 400hp to the wheels through a 3600 stall when I'm done with my n/a mods, and then a 100-150 shot on top of that, so I want to replace the trans with something that will last. I do drive it 50 miles daily and race 15-20 wide open passes weekly. If any sponsors want to chime in and make a buck I'd be glad to hear what you have to offer

 

Well you are welcome to look at what we have to offer on our website, However are you sure the ginding isnt actually happening as the converter goes in and out of lockup , If its not slipping at WOT and the feeling /noise only happen at part throttle that honestly sounds like it could be a converter clutch issue. I dont doubt you need to upgrade the trans for what your doing but the syptoms dont sound like a trans issue. After all the 4th gear shift is nothing more than the 2-4 band coming back on after the 3-4 clutch came on in 3rd.
hope this helps some

 

I guess that is possible, it could be when it goes into lockup. I just bought the stall a few months ago though and it's a vigilante, is it possible for it to poop out so soon?

 

Sounds like your converter, mine was doing the same. It took out my trans, had it rebuilt, and installed a new yank only to have the same problem and found out I had to have all the lock up table and shift tables