2009 Denali/Front diff question....

[swathdiver]

Recently, on LTs own youtube channel, he discovered that the internals of the AWD and 4x4 front differentials on the GMT800s were more different than originally thought. He goes through the differences.

I do not know if this translates to the 900s, would have to pour over the parts diagrams that AAM provides.

 

[91RS]

The AWD and 4WD differentials are different. Don't buy a used one, it will have or eventually have the same problem you have now. Buy a rebuilt one (especially if you intend to replace yourself) or have your's rebuilt and be done with it.

 

[intheburbs]

Exactly. You can also direct swap in a 4wd diff into a Denali and all you have to do is remove the actuator and there is a aftermarket place that sells an adapter that goes in place of the actuator and it pushes in on the lever to make the 4wd diff a AWD all the time diff. The adapter uses the original bolts of the actuator too and bolts right in place. This removes the work to changeout the extension housing and passenger sideshaft but as you said. That part isnt too hard to do.

Ok, so I'm a little confused here. An AWD vehicle needs a third differential to account for differences in speed of the front/rear when making turns. Crank the wheel of a 4wd vehicle on dry pavement and you get heavy resistance and tire scrub. The Denalis have that third diff on the pinion/input of the front diff.

If you're just swapping in a 4wd front axle and locking it in by removing the actuator, how is that going to work when you want to make a turn? You have no third diff in that setup.

 

[91RS]

Are you talking about the transfer case? The transfer case is different as well. The AWD differential is open and never locks.

 

[George B]

But why do a mod when you have the correct parts laying on the floor and all you need is a $20 gasket?
Genuine GM 15270970 Axle Shaft Housing Gasket, Front https://www.amazon.com/dp/B00F671PFQ/ref=cm_sw_r_cp_api_glt_i_B6J0XCGJ5R04QRYG0JRQ

 

[rockola1971]

Ok, so I'm a little confused here. An AWD vehicle needs a third differential to account for differences in speed of the front/rear when making turns. Crank the wheel of a 4wd vehicle on dry pavement and you get heavy resistance and tire scrub. The Denalis have that third diff on the pinion/input of the front diff.

If you're just swapping in a 4wd front axle and locking it in by removing the actuator, how is that going to work when you want to make a turn? You have no third diff in that setup.

Slippage between front and rearend is accomplished via the Borg Warner AWD Tcase. There is no "3rd differential". The AWD and 4WD front ends are the same (assuming same gearing) except for the passenger side of the front diff. The AWD does not have the actuator that a 4wd unit has. An AWD front diff is locked into "4wd" all the time. A 4wd front end can be locked into 4wd for AWD purposes (when installed in a AWD vehicle) by either removing the actuator and installing an aftermarket spacer/lever that actuates the lock in at all times OR by hot wiring the actuator to be on all the time which I do NOT recommend since the actuator is likely not 100% duty cycle rated and will live a short life. You could also remove the passenger housing of the front diff from a broken AWD unit and install in a 4wd unit. Its a direct swap. Both frontends are direct bolt in for each generation of K chassis.

 

[Mookon]

Slippage between front and rearend is accomplished via the Borg Warner AWD Tcase. There is no "3rd differential". The AWD and 4WD front ends are the same (assuming same gearing) except for the passenger side of the front diff. The AWD does not have the actuator that a 4wd unit has. An AWD front diff is locked into "4wd" all the time. A 4wd front end can be locked into 4wd for AWD purposes (when installed in a AWD vehicle) by either removing the actuator and installing an aftermarket spacer/lever that actuates the lock in at all times OR by hot wiring the actuator to be on all the time which I do NOT recommend since the actuator is likely not 100% duty cycle rated and will live a short life. You could also remove the passenger housing of the front diff from a broken AWD unit and install in a 4wd unit. Its a direct swap. Both frontends are direct bolt in for each generation of K chassis.

Will a Gen2 front end work in a Gen3 without major modification?

 

[rockola1971]

Will a Gen2 front end work in a Gen3 without major modification?

Thats one I do not know. Best bet is call a salvage yard and ask them if their interchange catalog shows that to be true or not.