I have an 2001 audi a6 2.8 quattro and I forked out over 3k to totally rebuild the transmission. My machanic is on the 3rd rebuild as I type this. The last 2 times I have gotten my audi back it drove great for about 3 days then started slipping and eventually went out just like the original when I took it in. Thankfully he guarantees his work so I have not been charged again. My question is does anyone have any idea what could be going wrong?? I really want my car back and I figured I would look into it my self. Thanks for any help on this.