Is my AWD Escalade rearend junk?

[73TA]

John, thanks for explaining things to me. I just never had a GM vehicle with limited slip rotate the wheels with almost no effort while it is in park. I know I keep repeating this, still wondering how the vehicle will not move if the rear diff appears to be basically disconnected internally from driveshaft yoke. I can rotate one tire with almost no effort and both tires spin easily, and it is in park.

However, I can hear a clunk when I change directions and see the driveshaft move slightly in each direction when I do that. It just seems like there is basically no clutches left in the rear diff.

There is no way my Esky would not roll down a hill unless the front diff is locked by the transfer case. Because the rear sure isn't.

Won't know for sure until I get home.


Mike

 

[George B]

How a G80 locker works.

jack up one rear wheel and try to spin it.

 

[73TA]

10-4, will check it out.

Mike

 

[sonic_the_hedgeh]

My project 08 Esky with 234K miles has been pretty good so far. Took it for a 300 mile road trip and got 17 mpg on the freeway. I have been noticing a "clunk" or something like that when taking off "briskly" from a stop or a downshift when accelerating on the freeway. So I jacked it up on the rear diff and the both wheels would spin. I thought this should be impossible if it is in park.
I then got underneath it and checked the u-joints and they looked fine. Then I spun the wheels. The drive shaft was not moving, so it definitely was is park.
I then put the front wheels on concrete with the rear wheels in gravel and tried to power brake it, the rear wheels did not spin the gravel. I assume that I have been driving with only the the front diff taking all of the load and pulling the Esky instead of it being "pushed" by the rear wheels?
Are the rear "posi" clutches worn out?

I am missing something here?

Mike

Project thread

https://www.tahoeyukonforum.com/thr...-mechanic-fixed-my-blown-engine-for-7.123682/

I would be shocked if your rear end is shot. I have an 04 Gmc Yukon Xl with 370,000 kms on it. The rear end is original. I have had the fluids changed a few years back in the whole drivetrain just to ensure it would keep running. They are really tough. Who knows but hopefully it's not the rear end.

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[1Duffman]

All of our trucks are limited slip rears, unless you have a base model 2WD whatever, and even then there is still a good chance its limited slip. Now our front diffs are open, 2wd 4wd Awd, doesn't matter they're open diffs. The AWD transfer cases are a viscus coupling, meaning it has to fling fluid and get warm enough to engage the front drive shaft putting power to the front wheels.

This explains it better:
http://www.silveradoss.com/forums/topic/4312-nvg-149-transfer-case-info/
I think what is explained here is slightly older then what you have. But its the same concept with either generation truck

1 single axle does not lock the vehicle in park. Dont park on a hill and pull either driveshaft. Dont flat tow unless you pull BOTH drivesafts.

 

[73TA]

Well, I know I keep repeating this question, why do both rear wheels rotate when the rear end is off of the ground when it is park (they driveshaft does not move because it is park) If someone is bored and they want to verify that this is normal I would appreciate it.

Thanks
Mike

 

[George B]

Well, I know I keep repeating this question, why do both rear wheels rotate when the rear end is off of the ground when it is park (they driveshaft does not move because it is park) If someone is bored and they want to verify that this is normal I would appreciate it.

Thanks
Mike

Do they both turn the same direction at the same time? Or does one turn one way and the other opposite.

 

[George B]

All of our trucks are limited slip rears, unless you have a base model 2WD whatever, and even then there is still a good chance its limited slip. Now our front diffs are open, 2wd 4wd Awd, doesn't matter they're open diffs. The AWD transfer cases are a viscus coupling, meaning it has to fling fluid and get warm enough to engage the front drive shaft putting power to the front wheels.

This explains it better:
http://www.silveradoss.com/forums/topic/4312-nvg-149-transfer-case-info/
I think what is explained here is slightly older then what you have. But its the same concept with either generation truck

1 single axle does not lock the vehicle in park. Dont park on a hill and pull either driveshaft. Dont flat tow unless you pull BOTH drivesafts.

A G80 in any of these SUVs is not a limited slip. It’s a locker. And when they lock they hop on dry pavement when you turn. If they are wore out they might not lock tight but they are not a limited slip with spring loaded disc packs.

 

[gooffeyguy]

Do they both turn the same direction at the same time? Or does one turn one way and the other opposite.

Mine turn in opposite directions.

The G80 acts like an open differential until it locks up from what I understand

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[George B]

Mine turn in opposite directions.

The G80 acts like an open differential until it locks up from what I understand

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Same with mine.