I'm in the process of installing new Motive 4.30 R&P in my '01 Sierra 1500 with the 8.6 rear end. I used the same thickness pinion shim as was on the factory pinion. I bought a pinion depth checking tool from Ratech, but's kind of difficult to get a good reading.
I installed the new Detroit TrueTrac using the factory shims. Amazingly, I've got good bearing preload with a backlash of .007". Here's the resulting pattern. I marked three teeth in two different locations. Take a look and let me know how it looks to those of you that have some experience with this. This is the second truck I've setup. But the other one was quite a few years ago. I've got the ability, but not the experience. Once again, please take a look and let me know ASAP. I'm waiting on your response to button this thing up
Thanks.
1st drive pattern

1st coast pattern

2nd drive pattern

2nd coast pattern
MORE POWER!!
'01 ECSB 4x4, 5.3L, 4.30:1 gears & Detroit TrueTrac, Coming Soon(TB Stall), 265/75 16, Comp Cam 212/218, .522/.529, 114LSA, LS6 springs, Trick Flow Push Rods, Doug Thorley LT Tri-Y headers, 24" glasspack/resonator + FlowMaster Delta 40 muffler, 180* t-stat, LS1 e-fans, Nelson harness, Airaid MIT, 145A Delco alternator, W4M tune - no TM, Complete valve body build up, Ford Keys, Rear Add-a-Leaf, Painted mirrors w/chrome caps