2006 Denali Transfer Case Howl

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Rocket Man

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Thought I'd reiterate for future purposes, that according to the BW specs for the 4481, truck shouldn't be run when on the lift.
I had to look up what you were talking about. So yours is the NR3 RPO code which is the Borg Warner 4481. Interesting. Different than mine.
 
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easterr

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Oh, yours is a 2002. Yeah, the change to BW4481 was 05, I think. BTW, 2 mechanics who looked at the Denali were not aware of not running it on the lift. Should I still assume all 4 wheels should spin? Both mechanics were convinced the transfer case is the reason for the grinding and vibration I feel, which feels awfully like the front differential from what I've read. I have to drain it and see if there is metal pieces. I sure hope it was damaged by the first mechanic running it on the lift.
 
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easterr

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Is the "differential pinion gear" noted in the GM service specs in the axle differential and not the TC? For those interested the GM service excerpt is below.



The Borg Warner (BW) model 4481, RPO NR3 transfer case is a one-speed, full time, all wheel drive (AWD), transfer case. The transfer case provides power to both axles, through an external planetary type differential, which has two different sets of pinion gears. The planetary differential provides a 40/60 torque split, front/rear, full time. This means both axles are constantly being driven for maximum traction in all conditions.

The transfer case external type planetary differential functions the same as a typical rear axle differential. The transfer case differential pinion gears function as the spider gears, and the sun gears function as the side gears.

The following actions occur because of the planetary differential:

•If the vehicle is on a hoist, the front propeller shaft can be rotated by hand.
•The vehicle cannot be driven if one propeller shaft is removed.
•Operating the vehicle on the hoist can damage the differential pinion gears, by over-spinning.
•Operating the vehicle with one propeller shaft removed causes over-spinning of the differential pinion gears.
The BW 4481 design of the planetary differential allows the use with the Vehicle Stability Enhancement System (VSES) vehicles. The VSES takes use of the planetary differential, by applying braking to a tire that has less traction and dividing the engine torque to the other axle.

The BW 4481 case halves are high-pressure, die-cast magnesium. Ball bearings support the input shaft, the front output shaft, and the rear output shaft. The transfer case requires DEXRON®III ATF GM P/N 12378470 (Canadian P/N 10952622), which is red in color.
 

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The pump wear people speak of here applies to the NP246 transfer case which is 4wd NOT AWD. The Borg Warner AWD models didnt have this issue. You should never run a AWD vehicle on a lift. Its sucks because its an easy way to troubleshoot but it is what it is.
 

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