my 1998 audi a6 2.8 has a small leak in the trans like really small and the mechanic said one of the gaskets is bad and theyd have to drain the trans fluid all out and fix it and add new but wouldnt that ruin my trans since my car has 100,000miles on it? cause they say not to touch the trans fluid when its at high mileage...

You should be alright, when I was doing my stage 3- I dumped all the fluids and replaced with fresh and new, no issues to speak of so far.

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stage 3- A6, with a little meth

Now why wouldn't you change the fluid? All fluids will require changing after some time. Fluid gets crap built up inside of them (floating around) that can cause further problems down the road. IMO, changing you tranny fluid after 100k would be a good thing.

While at it, have them change the filter too.

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2001 A6 Avant
2.8 ATQ, Quattro, Tiptronic
Mods - SpeedTuning Chip, K&N
Repairs - Too many to list! And you wonder why I still drive an Audi

sidekicklxondeck, I agree and see your point. I have always been carefully not to open a closed system after a certain mileage. I had a 86 F-150 w/ 5.8 HO 351 that had 160k+ I decided to open a swap out the fluids and filter and tranny problems occured shortly after. Again, had a 1998 Buick Regal Gs (supercharged) fun car, w/ 135k+ same situation. Although, I am not an audi tech or audi engineer I personally wouldn't change it under any preventitive measure. But given your ceratin circumstance I would go ahead and address the problem. Do you trust this mechanic?

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The greatest trick the devil ever pulled was making you think he did not exist...then poof, he is gone.

01 2.7T
Stage 2