AWD help

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Ty Stud

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I have an 07 Denali running 35s on BDS lift. Purchased this rig in January for my wife so I could get back in my ‘11 Dmax...turns out she doesn’t like it likes the pickup better. Well good news is I really like driving the Denali, never thought I would go back to a gasser. Anyway this AWD system is confusing me a little I’ve had it in a little mud and sand and it really did surprisingly well. Just ease on the throttle and let the rig do it’s thing right?...Anyway yesterday I tried to get back into our cabin and there was still 8”-12” of snow on the driveway. I figured no problem since it’s been melting and I can dig down to the gravel drive if I really get stuck. So I start breaking trail about 10-15 feet at a time (going forward then backing up making sure I have a good trail) any about 200 feet in I get stuck in a shaded drift and my brother-in-law tells me my front wheels aren’t turning. I turn traction control on and of turn the rig on and off we check fusses and they are all good. We get it dug out and moving again for 20 or 30 feet and there was a clunk and then I’m driving through my tracks again like it’s bare road. Is there any reason the front diff would be able to disengage or did I do something wrong here. Anyway sorry for the long winded question I’m just a little disappointed in the rig and might wish it wasn’t a Denali. Thank you for any input and help.
 

wjburken

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I have an 07 Denali running 35s on BDS lift. Purchased this rig in January for my wife so I could get back in my ‘11 Dmax...turns out she doesn’t like it likes the pickup better. Well good news is I really like driving the Denali, never thought I would go back to a gasser. Anyway this AWD system is confusing me a little I’ve had it in a little mud and sand and it really did surprisingly well. Just ease on the throttle and let the rig do it’s thing right?...Anyway yesterday I tried to get back into our cabin and there was still 8”-12” of snow on the driveway. I figured no problem since it’s been melting and I can dig down to the gravel drive if I really get stuck. So I start breaking trail about 10-15 feet at a time (going forward then backing up making sure I have a good trail) any about 200 feet in I get stuck in a shaded drift and my brother-in-law tells me my front wheels aren’t turning. I turn traction control on and of turn the rig on and off we check fusses and they are all good. We get it dug out and moving again for 20 or 30 feet and there was a clunk and then I’m driving through my tracks again like it’s bare road. Is there any reason the front diff would be able to disengage or did I do something wrong here. Anyway sorry for the long winded question I’m just a little disappointed in the rig and might wish it wasn’t a Denali. Thank you for any input and help.
Your AWD has nothing that engages/disengages in the drivetrain. I would take a good look at your front differential and see how much play you have in it. How many miles are on the vehicle?
 

Bill 1960

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There’s got to be a center differential in those, so it’s quite possible for one end to spin and the other not. Unless there’s a torque vectoring mechanism like clutches or viscous coupling etc. I’m not familiar with the internals of that transfer case, hopefully someone will comment who knows more.
 

Geotrash

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There’s got to be a center differential in those, so it’s quite possible for one end to spin and the other not. Unless there’s a torque vectoring mechanism like clutches or viscous coupling etc. I’m not familiar with the internals of that transfer case, hopefully someone will comment who knows more.
There is a viscous coupling in the transfer case that allows the power to be distributed between the front and rear axles as needed. It's possible it got overheated.
 
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Ty Stud

Ty Stud

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Your AWD has nothing that engages/disengages in the drivetrain. I would take a good look at your front differential and see how much play you have in it. How many miles are on the vehicle?
Okay great thank you 170k
 
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Ty Stud

Ty Stud

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There is a viscous coupling in the transfer case that allows the power to be distributed between the front and rear axles as needed. It's possible it got overheated.
That makes sense thank you I appreciate the response.
 

bigdog9191999

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what geotrash said. the case could be overheated or possibly failing . i know i have been bumper deep with our denail and she powered through with no issue, but i didnt push it for the time/distance your working with.


if you end up needing a replacement seems like it it denali/escalade and another that use it.. it is a little spendy but they usually last decent. ours has 245k on it. and it has towed alot.
 
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Ty Stud

Ty Stud

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what geotrash said. the case could be overheated or possibly failing . i know i have been bumper deep with our denail and she powered through with no issue, but i didnt push it for the time/distance your working with.


if you end up needing a replacement seems like it it denali/escalade and another that use it.. it is a little spendy but they usually last decent. ours has 245k on it. and it has towed alot.
I’m sure it’s a combination of it getting hot and being wore out haha anyway thank you for your response I appreciate it.
 

HD_LS

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On an 07-14 Denali, the AWD transfer case is a straight planetary differential with a 40% Front, 60% Rear torque split. No clutches, no viscous coupling, no locking. Always 40/60 torque split. So simliar to a rear wheel drive vehicle with an open differential, if one wheel is spinning, the wheel that is not spinning gets the same driving torque (which is virtually nothing). So 1) If the rear tires are spinning, and the front ones won't turn at all: Then you can apply the emergency brake to get more drive shaft torque to the rear, which will get you more torque to the front. 2) If the front wheels are spinning, but the rear ones won't turn: You can apply the main service brake while under throttle. Or to get really serious, I suppose that you could get a line-lock kit so you can hold brake pressure on the front's only. The ABS/Stability control system is rumored to have the capability to brake the wheels that are spinning, to get more torque to the ones that are not. But I am not sure if or how well that system works at doing that. Multiple reports of what you observed seem to indicate that it does not work well if at all at doing that.
 

Geotrash

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On an 07-14 Denali, the AWD transfer case is a straight planetary differential with a 40% Front, 60% Rear torque split. No clutches, no viscous coupling, no locking. Always 40/60 torque split. So simliar to a rear wheel drive vehicle with an open differential, if one wheel is spinning, the wheel that is not spinning gets the same driving torque (which is virtually nothing). So 1) If the rear tires are spinning, and the front ones won't turn at all: Then you can apply the emergency brake to get more drive shaft torque to the rear, which will get you more torque to the front. 2) If the front wheels are spinning, but the rear ones won't turn: You can apply the main service brake while under throttle. Or to get really serious, I suppose that you could get a line-lock kit so you can hold brake pressure on the front's only. The ABS/Stability control system is rumored to have the capability to brake the wheels that are spinning, to get more torque to the ones that are not. But I am not sure if or how well that system works at doing that. Multiple reports of what you observed seem to indicate that it does not work well if at all at doing that.
I stand 100% corrected. The BW4485 is a straight planetary differential. The NV149 in the older trucks has the viscous coupler.
 

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