[solarflare]

I bought a subscription to alldata, and found the issue. There is a revision of the original update that takes care of the clunk that I have been hearing. Here is the info:

Bulletin No.: 08-07-30-012

Date: March 13, 2008
Subject:
6L80 Automatic Transmission - Tip In Low Speed Clunk in First Gear When Throttle is Applied and Released, Engine Braking Sensation at Low Speeds (Reprogram TCM)

Models:
2008 HUMMER H2, H2 SUT

with 6L80 6-Speed Automatic Transmission (RPO MYC)

Condition

Some customers may comment that the vehicle has a "Tip In" low speed clunk in first gear when the throttle is applied and released in normal "D" drive. Other customers may comment on an engine braking sensation at low speeds in normal "D" drive.

Correction

A revised transmission calibration has been developed to address these issues. Reprogram the transmission control module (TCM) with updated calibration files using the TIS2WEB Service Programming System (SPS) application. As always make sure your Tech 2(R) is updated with the latest software version.

Warranty Information