The dealer had to reflash or replace my prom and I started over. Not sure if my truck had a bad ECM prom before I started, but to recap:
When you first have the gears installed, the traction control will be whacked because the sensors are getting bad information. What happens is the vehicle dies when it hits second gear, no matter what speed you are moving at. This can be hazardous to your health the first time it happens as you pull out into traffic from the gear shop. You will have to disable the T/C manually until you get into the ECM to tell it you have a new gear ratio. Dealers CANNOT do this with standard GM software - you must use an aftermarket tuner.
Here is where it gets painful - I tried Crane and Superchips tuners, neither would even load on my truck. I then tried a Granatelli, which would load, but things got even crazier. Now my speedo error got WORSE, and the T/C light came on permanently, GRRRRR. This all takes time, I'm driving a crippled truck for almost a month trying to sort this all out. Back to the dealer let them work over the ECM (they fixed a bunch of other issues too), and this time I grab a different Granatelli off the shelf, and it works PERFECTLY. I'm rockin now. I've raised my shift points and rev limits, installed a very aggressive tune (requires 91 octane), firmed up the shifts, and I'm driving a REAL HOT ROD, not a poseur. And with the Magnaflow exhaust, it SOUNDS like one too.
Thanks Jim for all your hard work on this stuff, everything you've posted has been true in my experience, and at this point I can't recommend the gear change enough to others... :seeya