2008 Sierra Denali Awd System Question/complaints...

BraemerZ28 · February 17, 2009

We went snowmobiling in the UP of Michigan this weekend. I had a two place snowmobile trailer with 4 guys and gear in the truck. Trailer was probably around 2500 lbs loaded, gear in the bed was about 500 and guys around 220 each. I'm running a 2.5" + 1" Truxxx leveling kit with 33 x 12 Cooper Zeon LTZ's which are M&S rated tires. This truck should have ZERO problems in anything less than 10" of snow with these tires and that much ballast on board. Heck, my 2000 Sonoma could have handled that - other than the 4 guys part.

I got stuck THREE DIFFERENT TIMES trying to back the trailer into various drives and parking spots. As soon as I would get any load or resistance of any sort (one front wheel in an ice pile, slight hill, etc) the rear wheels would lock together thanks to the mechanical locker (that's good ) and start to spin while the fronts would go nowhere (that's bad ). The traction control lights would come on and there would be a beeping, but no front wheel spin - on either side, in any of the 3 "stuck" situations. The good news is that I was able to go forward in all instances so there was no shoveling or winching, but I'm still VERY disappointed in the truck right now.

Question: Would turning off the traction control and or stabilitrack have made a difference? Is there anything that would make a difference here other than trading the GD thing off or swaping in a real transfer case?

Thanks,

BuckFeverZ · February 17, 2009

Yeah turning traction control off would've help. It would have let you get more wheel speed.

pchrist · February 17, 2009

you didn't try to turn traction control off to see what it would do??? I don't have it in my truck but have driven 08's that have it and it really helped in 2wd but would think in 4wd it might be a nuisance????

We went snowmobiling in the UP of Michigan this weekend. I had a two place snowmobile trailer with 4 guys and gear in the truck. Trailer was probably around 2500 lbs loaded, gear in the bed was about 500 and guys around 220 each. I'm running a 2.5" + 1" Truxxx leveling kit with 33 x 12 Cooper Zeon LTZ's which are M&S rated tires. This truck should have ZERO problems in anything less than 10" of snow with these tires and that much ballast on board. Heck, my 2000 Sonoma could have handled that - other than the 4 guys part.

I got stuck THREE DIFFERENT TIMES trying to back the trailer into various drives and parking spots. As soon as I would get any load or resistance of any sort (one front wheel in an ice pile, slight hill, etc) the rear wheels would lock together thanks to the mechanical locker (that's good ) and start to spin while the fronts would go nowhere (that's bad ). The traction control lights would come on and there would be a beeping, but no front wheel spin - on either side, in any of the 3 "stuck" situations. The good news is that I was able to go forward in all instances so there was no shoveling or winching, but I'm still VERY disappointed in the truck right now.

Question: Would turning off the traction control and or stabilitrack have made a difference? Is there anything that would make a difference here other than trading the GD thing off or swaping in a real transfer case?

Thanks,

VMax2007 · February 17, 2009

Yeah turning traction control off would've help. It would have let you get more wheel speed.

+1

And a real 4wd system would have helped too. This is why I chose my truck over an AWD Denali.

AWD is great for on-road traction/handling, but not the best set-up for off-road or deep snow conditions.

redvett · February 17, 2009

Smaller narrow tires would have helped too.

BraemerZ28 · February 17, 2009

you didn't try to turn traction control off to see what it would do???

Yeah, by the time I got the rears spinning and a bunch of "input" from my friends on how my 4wd truck only had 2wd, I just pulled forward and parked without bothering to push buttons to try and prove a point. We're supposed to get some more snow tomorrow. I might find a field someplace and do some screwing around to see how various settings behave.

VMax2007 · February 17, 2009

Yeah, by the time I got the rears spinning and a bunch of "input" from my friends on how my 4wd truck only had 2wd, I just pulled forward and parked without bothering to push buttons to try and prove a point. We're supposed to get some more snow tomorrow. I might find a field someplace and do some screwing around to see how various settings behave.

Well, you don't have a 4wd truck, you have an AWD truck. Big difference. As you found out.

pm26 · February 17, 2009

Do AWD trucks have a low 4WD range? I doubt it, but I am not sure, as I never owned one of those.

The low range is great for pulling boats out of water on a boat ramp because you basically double your torque at the rear wheels and the truck does not struggle at all. The same would apply to backing or pulling a trailer in deep snow.

robot225 · February 17, 2009

Nope. No low range in awd.

BuckFeverZ · February 17, 2009

Do these Denali's come with G80's??

Rat4go · February 17, 2009

The big advantage with a 'real' 4wd system is that you can lock in the tranfer case, guaranteeing that you have torque to the front axle as well as the rear. 4 low would likely not have helped as much as just getting torque to the front axle. I've found in snow with my 2500 that 4 low is just an easier way to break traction due to the extra torque multiplication, so when things get slimey, I'm usually in 4 High.

With the G80 engaged, a 4wd system is at least a 3WD system (front diff is not a locker stock so you can only guarantee torque to one front wheel) where the AWD system relies on electronics to measure speed differences and split torque front to rear. From your comments, doesn't do a very good job of it in certain situations. Next time, try either a gentle throttle, or killing Traction control or both and report back!

Where in the UP were you sledding??

Matt_ · February 17, 2009

The tcase of awd is basically a centrally located differential. Granted it does have some ls properties built into it, it sounds like your rear tires lost enough traction to render the front axle useless.

You have plenty of power with your 6.2l. Applying the brakes and light throttle would have likely brought you wherever you needed to go.

AWD is very capable when used properly. However unlike 4wd, wheel speed is your enemy- hence why awd is not a great mudding truck....

To answer another question- my 08 SD has a G80... I think its standard

ChrisNJ · February 17, 2009

I have the AWD 6.2 and don't like it, the AWD part. AWD doesn't belong in a truck that people use as a real truck. Next truck will be the 6.2 w/normal 4x4 transfer case, but they didn't offer it in 07. On the other hand, it has been great in my wifes Yukon XL Denali, I never have to 'teach' her what to do. I have to be carefull with it tough when we have the 8K lb trailer on it though and are in muddy fields at the races. It hasn't gotten stuck yet, but I've been close.

ChrisNJ · February 17, 2009

another note. I do remember when pulling the trailer up a hill in the mud all four wheels were spinning.

PhilB · February 17, 2009

The tcase of awd is basically a centrally located differential. Granted it does have some ls properties built into it, it sounds like your rear tires lost enough traction to render the front axle useless.

When the trailer got stuck, it probably pulled the rear of your truck up a bit which caused the rear tires to lose traction. Just a thought.

Phil