Im working the same topic.. check my threads.. Apparently the whole engine harness needs replaced as well as driveshaft (s) and the shifter on the column.. Then needs tuned to reflect having a 6L..

Lots to it..

 

you dont need the column shifter, stock will work.

 

Seems to be a bit involved, but not too bad. With the stock shifter you cant utilize the manumatic shifting, right? Doesnt the 6 spd shifter have a rocker switch to go thru the gears, as opposed to the tow/haul button? Also, what about the gauge cluster display? Will a tune reset the computer to reflect the change to a 6 spd on the display, or does it need to be replaced with the proper unit?

 

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tow haul button will work but the 123 gears on cluster dont, and the stock shifter does not have manual shift, so if you want all that options go with the escalade-denali shifter, or stock will work