Towing the HQ?

[HK1837]

http://en.wikipedia.org/wiki/GM_4L60-E_transmission

Not sure why that link says 2004 only for 4L65E for Crewman and tonner. Must mean 2004 onwards.

[Innuendo]

Not sure why that link says 2004 only for 4L65E for Crewman and tonner. Must mean 2004 onwards.

The claim appears to be that all but 2004 models used a 4L60-E and not a 4L65-E it is certainly not onwards as early VE V6 still use the 4L60-E.
Later they would switch to 5L40-E (5 Speed) and 6L50-E (Six Speed) and the 6L80-E for the V8. Or so it reads!