The older AWD stuff (syclone, typhoon, bravada, AWD astro van) used viscous coupling which split the tq 65% rear 35% front but I dunno if gm still uses that technology. The later transfer cases that Ive torn down (only two of them so Im no expert) had clutches/steels just like the stack up in an auto trans rather than the viscous coupler. There was a force motor that applied varying pressure to this clutch stack to send more or less power to the front depending on what the PCM commanded.

It'd be nice if someone with way more computer smarts than me could hack the code on that xfer case so when youre at the track you could back off the force motor so the rear tires could be heated without hurting it then reapply the force motor so you'd be back to AWD. Even better would be once you launched the force motor could be slowly backed down as MPH increased and the need for AWD diminished. It'd be nice but all that is WAY above my head so I'll have to wait on someone else thats smarter to figure it out and market it .

 

Yes it uses viscous coupling

 

I do. Shoot me a pm if interested.

 

I was under the impression that the Tahoe SS used a Torsen style center differential.

 

This is good stuff...

 

the trans r the same the trans fer case is diff.

 

For what its worth, the Yukon Denali's and Escalades use a Borg-Warner 4481 T-Case. Which is a planetary style differential, rather than a viscous coupling which is found on the Sierra Denali and Silverado SS.

 

which is stronger?

 

i do know up until 2004 in the sierra denali's... the awd case is a nvg-149 all mechanical.." not a computer controlled, or brake assist.. transfer case".. i have been pretty impressed with it so far, i truly believe the awd system that gm had in the nvg-149 is the best i have seen... in all applications...especially in snow and sand ...except for hardcore offroading...and i have owned a few older 4x4 trucks...true lockers and the bit.....

 

The NVG 149 is viscous coupled.