Agreed. It's pretty hard to avoid the sudden "shock" that a manual throws at the rear end . With an auto, on the other hand, you can pre-load the drivetrain before launching the car, so the gears are already in full contact, and have very good odds of "not breaking" when you run.

I broke the 4.10's that were in my car behind the A4 (sheared 2 teeth off the pinion) but it occurred while road racing the car, not drag racing. I dragged the car lots with no problems. On the road course, it was a different story. Constant "on the throttle, off the throttle" with automatic 2nd gear downshifts at EVERY corner ..... it lead to the death of the 4.10's and my 4L60E all in one weekend!!!

Have I bought a 12-bolt yet?? No. Do I plan to?? Eventually. Right now, gear sets cost ~$350 (CDN$). A 12-bolt is over $2000. Considering I just spent ~$3k to swap to the T56 (I would have spent close to that to re-build the A4 and add a stall anyway) I don't have the money right now for the 12-bolt. I know I'm still playing with fire (especially considering I've now got a T56) but for me, I have plenty of experience pulling apart the 10-bolt, so for a couple hundred bucks here and there, I'll keep screwing around with this for now UNTIL ... .