My 11 GS transmission appears to have a big problem. I made a couple of passes (at the track) with some 17 MT's (first time trying them) and noticed a weird hesitation when it hooked up, seemed to pull let up and pull, but otherwise went down the track (1/8) pretty good 6.65. Since that run it seems to have shifted fine, but when I come to a red light sometime I put it in neutral, because with the cam it kind of bucks a little. When coming to a stop, put it in neutral and a second later I hear and feel like something engages or disengages in the trans. It is hard to explain, but it is like feeling something spinning and then it finally locks up while sitting at the light. Now last nite I got on it again pretty good and felt a similar sensation like I had at the track. I had to drive about 60 miles to get home last nite and by the time I got off at my exit I noticed slippage in 3rd or 4th and it got progressively worse at each stop & start till I got home.

History; the trans is stock as far as I know and after buying the GS, I had a new triple disc 3200 converter put in after finding the previous converter with the nose in 3 pieces. Question; does any of this sound familiar to anyone, if so, what was the fix? I am sure it will be a rebuilt or new trans next, but I wanted some of you with trans. experience to chime in...thanks

 

IMHO you have slipping clutches in the transmission. Check fluid level and if that is OK, be prepared to spend some $ probably sooner rather than later. With a modified engine, I would seriously consider a RPM transmission rebuild. These guys know what they are doing and can build a bullet proof one for you.

 

Rpm doesn't rebuild the 6L80 anymore. I'd do like CHJ said and check the fluid level 1st. I've heard several guys have that fix whatever problems they were having and I remember 1 was something to do with an odd launch at the track. If it ends up needing rebuilt I'd recommend century transmissions on Houston area, they are the only ones I could find at the time that offered a warranty with their trans tune. The century trans is the longest lasting one I've had too, going on 4.5 years now.

Good luck

 

Add an extra 1/2 to 1 full quart of fluid beyond the standard full check method. It sounds like the converter is cavitating.

 

With the power you are putting to the ground I am surprised the stock trans lasted this long . There are not many options for a built A6. I have a Century in my 12 GS but I have not been down the strip yet. This is the second one in the car as the first unit gave out when my builder was testing the car on the street just after the install. The big guys (Rossler, RPM) will not do an A6. The only other A6 builder I know is Circle D. I hope the Century holds up or an A4 or Powerglide conversion is in my future.

BIGMAC

 

I determined that it is 4th gear slipping and I have a couple of things to check before surgery; check fluid level (recommended to be slightly over filled) and then Circle D transmissions advises transmission tuning is a common problem with slippage with the 6l80e. I will check these two out before I get too excited, but then again I don't have much faith in the easy solutions.

 

Slipping bands and clutches have it tuned i had same problem it was gone when tuned.

 

Adding an extra half quart of fluid fixed my problems with the same issue your having.......it would launch good then it would go off like clutch being pushed in, then back on for the rest of the run. Also a good tune is an absolutely a must!

 

Is there a certain HP/Tq level that these transmissions are limited too?
I have 2 friends right now that are on their second go round at $10K each. One is an A&A blower setup and the other was a blower setup but now N/A.

I don't wanna reach this level

 

With the right tuning and cooling , they can hold plenty of power when properly built. In stock form they won't last long with big power if run hard all the time.

 

The car is currently getting a cam, CAI, Kooks 1 7/8 headers and X pipe with no cats, and Nitrous Outlet plate on a 150hp setting, and a Pat G tune. I understand his transmission tune is very nice. I also hear that the tune on the transmission can also make it live longer if done right. Is this accurate?

 

The tune is key to making it live and Pat knows what he is doing, so you have a good chance.

 

That's what I hear and I hope so.