Denali AWD disappointing

[Davidd]

anyone know how this system works? Very frustrating, both this 2013 and a older escalade that I was driving got stuck off road and I couldn't get any power to the front wheels, ended up getting stuck. Both circumstances were similar.

Both vehicles ended up hung up on the rear, once on a ball hitch with too much drop, then fell into a hole and the rears free spun. Last weekend, the denali fell into a muddy wet rut and landed on the spare tire underneath. The tires were suspended in the ruts and rotated freely. There was no power on the fronts which would have enabled me to pull free pretty easily. I tried turning off the stability and traction control, pumping the brakes and a few things to make the fronts engage but no luck. Was stuck for 2 hrs.

The awd system is not broken, I use it off-road weekly and it kicks in most of the time and pulls me through mud but in the above scenario, the systems doesn't seem to know it is stuck.

I know this vehicle isn't designed for any real off-roading but it's what I have and just wondering if anyone knows how the system works, why it doesn't work when hung up as described and if there are any tricks to engage the fronts.

 

[kbuskill]

It's because of the viscous coupling in the transfer case.

As you already stated... AWD is not really for offloading.

Here is a good read on the subject:

http://www.awdwiki.com/en/viscous+coupling/

 

[SethSwitch]

I would suggest putting on your parking brake if this ever happens again. That should put resistance on your rear wheels and allow the system to get a greater torque split to the front wheels.

 

[Doubeleive]

next time that happens just pull the fuse and you will have a full power to all 4 wheels, it will give you errors on the dic just disregard and drive, even with disabling the stabiltrac etc on the dic it's still active to a certain degree until you completely disable it. some people have even just added a toggle switch to do it on command.

 

[Davidd]

/doubeleive

Will this really work and if so, where is the so called fuse bc it is going to happen again. And, once I put the fuse back after getting out of the predicament, will there still be error codes or will it resume working normally without errors?

 

[Ex Euro Driver]

It's because of the viscous coupling in the transfer case.

As you already stated... AWD is not really for offloading.

Here is a good read on the subject:

http://www.awdwiki.com/en/viscous+coupling/

Pretty much agree with this. You’re definitely pushing an AWD vehicle to its limits and beyond. The Tahoe with its selectable 4wd hi/lo might be a better choice for the given terrain.

 

[Doubeleive]

first video just skip to the end to see where the fuse is

second video is different fuse box the idea is the same if you wanted to patch in a toggle switch pretty easy

 

[intheburbs]

Power Flow - Rear Wheels Slip

When traction is lost at the rear wheels, the torque is biased to the front wheels. The torque to the front output shaft (3) goes higher from the 38 percent, up to 100 percent torque. The torque at the rear output shaft (2) is lowered from the 62 percent, to as low as 0 percent torque.

Customers may have concern that the transfer case is not operating properly because one set of tires spun for a brief period. It is normal for one set of tires to spin until the viscous coupling engages.

Turning off the traction control switch, if equipped, enhances the function of the viscous coupling. The viscous coupling, as described above, engages by heat. Allowing one set of tires to spin or slip for a brief period will generate heat in the viscous coupling. The engine speed should be kept at a constant speed during the brief spin of the tires. Pulsating the engine speed or hard acceleration will not allow the viscous coupling to operate properly.

 

[Davidd]

I put the vehicle in gear and the tires were spinning freely, with and without throttle. The fronts would never kick in, with or without traction and stabil control. As soon as I got pulled free, I hit the gas and could tell the fronts kicked in. There is something about the rear being slightly suspended and the tires spinning that seems to cause it to be unaware that it is stuck or needs front power.

Not sure the fuse idea will work. Would be happy if so but not so sure

 

[Davidd]

Duplicated post, sorry