I had to go in to the dealership/service department a couple of days ago to fix the P0441 code I got. I returned my program to stock with SC before I went in and they performed the repairs needed. I also told them I had some shifting issues while towing and had a copy of TSB 18-013-04 with me which they used to perform the appropriate tranny flash.
I have since re-programmed with SC to performance, and now I'm experiencing better shifting than I had before. At any speed, in any gear, I get a shorter delay it takes for the rpm's to build and for the torque to be applied to the rear wheels. The shifts are firmer and have a more positive feel to them.
I originally thought that the SC program would completely overwrite whatever transmission programming existed and install it's "own", but from what I've experienced it seems that SC has improved and enhanced whatever programming existed. In my case, the TSB flash improved what I had, and SC then improved from that point.
I'd like to know if anyone else has experienced this which would suggest that if you haven't had the tranny flash done, get it done. Then again, maybe my experience is the exception to the rule???
Now I cannot WOT from a standing start because the tire (peg-leg) spins way too much... I see an Auburn posi in my future.