Muhammad

I heard that a new 6-speed is being developed for the B6 S4, and perhaps that could mean it would work on the RS6 as well... and other high-performance models from Audi in the future.

I guess the problems with the ZF unit in the S4/S6/S8 led to it not being used in anything beyond the 2.7TT engine horsepower or torque-wise. That and marketing reasons, perhaps.

While it would make more sense to me that a 6-speed would handle the torque of the RS6, for example, better than a ZF tip, I guess that's not the case, and there are reliability issues with that particular transmission being used on cars with high torque output.

Makes you wonder what the long-term effects of chipping or other modifications to the 6-speed A6 2.7Ts and S4s might be on the 6-speed. The tip, I haven't heard of many problems.

Just speculation, of course. =)

nikhil

it really depends where you are putting the stress. Once you have more power than the drivetrain can handle, SOMETHING must slip. In most cars, esp. rwd ones, the tires will spin..so there isn't really that much stress on the drivetrain after the clutch initially slips. The stress in an AWD car is that nothing really slips, so something must break eventually. If you have a clutch that doesn't slip at all, then you will break wear out the differentials. There is no doubt that chipping will wear things out faster. The problem with the S4 trans was the pressure plate sticking and not being able to handle the torque of the motor, which explains why there is no 6-speed in any Audi with higher output than the S4.

Bollinger

The tranny handles all the torque the engine puts out times the lowest gear multiplier.

Extra power breaks drivetrains, it's true of racing everywhere. Heck, look what the least reliable part of the Audi R8 is: the drivetrain. Put too much power in and you may very well wreck your tranny. Them's the breaks.

brian 4.2

I'm impressed that they are putting that extra torque thru a modified Tip.

nikhil

I agree the weakest part is the drivetrain, but the trans isn't necessarily the part that will break

Richard Solomon

The S6 lost the 6spd in MY2001, IIRC. I believe it's rated for much more torque than the autos.

Modded tips are generally less agressively modded than manuals - see various ECU s/w vendors' sites for lower torque outputs on tip versions of the s/w.

If Audi quits putting transmissions in cars, I'll be over in bimmer land begging them to put AWD in their bigger cars

Keith J

While its true torque is what stresses the transmission, power only comes into the wear factor on bearings, mating surfaces etc. that are speed dependent. Most of the gearing is far more robust than required but the bearings are the weak link. Exceed their PV value and their life will be much shorter. Gears are designed for torque, bearings for torque and speed.

On Audi's, the cases are optimized for weight and mostly cast aluminum. Unless the bearing housings are beefed up, increased torque will shorten the life.

Upping the power should not affect the life of the transmission if the torque peak is not significantly increased (except in RPM range).