No it's just the opposite, AWD means all the time drivetrain is working. 4wd is only when 4wd is selected. In AWD there is a center clutch to slip between front and rear when taking tight corners.

Wannabe

My wife has an 09 Yukon Denali XL with the 6.2.Before I got it for her I drove a Yukon XL with the 5.3.Its night night and day performance wise.And the Denali has AWD the Yukon with the 5.3 just had 4 wheel that could be turned on an off.

Around town wife gets around 14 but on the highway we have seen 18.

Agreed as far as the AWD version. Would you agree that on the 4WD that the front drive shaft and front axles are turning since they're still "locked in" at the front wheels even when it's in 2WD mode? That's my line of thinking.

No in 2wd mode the front shafts and hubs do not turn. The GM system uses automatic locking hubs. Ford on the other hand uses manual hubs on many (not all) of their vehicles.

Wannabe

Yes, and the dodges don't have locking hubs at all... Ford hubs have been notoriously problematic in auto mode, although if you get out and lock them in manually, they'll work.

Hmmm that's strange. I know I've seen the front axles turning on a lifted '02 or '03 Burb while in 2WD mode and I know my drive shaft turnes on my '04 Avalanche while in 2WD mode. Now I'm really curious, so I guess I'll look at my truck in the morning.

Since when? All GM 4wd vehicles use CV half shafts, at least since 1988 (for full size). There is a disconnect that unlocks the long side shaft from the differential, but that's it, no automatic hubs. Unless it's changed in the last year or so...but I would be surprised.


GM hasn't used 'hubs' since they put a solid axle under the front of the trucks/blazers/suburbans (granted the subs/blazers didn't change body style/axle until 91-ish).

Thanks for the advice. She drove a camaro ss and liked that. It's going to be a tough choice.

My '06 6.0L 3.73 AWD Denali XL was lucky to see 16 MPG highway. This is hand calculated mileage, not going off the DIC. It never passed a gas station it didn't want to pull into. I liked the extra power over a 5.3L truck when towing. If it is a daily driver that will only see occasional light towing duty, I would stick with the 5.3L.

+1......My wife has a 2009 2WD Yukon 5.3 and real life is 14 around town, 16-17 highway (not towing anything). Truck has 45K miles on it and no issues except for the rear door lock failed. It would lock/unlock about one out of 10 times.