BW4485, rpo NR3, info

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donjetman

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In our AWD 07 Denali:

About the BW4485

The BW4485 design includes the use of a planetary differential enables the use of the Vehicle Stability Enhancement System (VSES) in larger GM upper end vehicles. The VSES makes use of the planetary differential, by utilizing braking to a tire that has less traction and dividing the engine torque to the other axle.

The Borg Warner 4485, is RPO NR3 transfer case it is a single speed, full-time, all wheel drive (AWD), transfer case. The transfer case provides power to axles, 40/60 torque divide, front/rear, full time through an external planetary type differential, which has two different sets of pinion gears. Both axles are constantly being driven for maximum traction in every conditions, have proven to provide slightly lower fuel mileage and more tire wear.

The transfer case external type planetary differential functions the same as a typical (open) rear differential, differential pinion gears work as spider gears, as well as the sun gears function as side gears. The BW4485 case halves are high-pressure, die-cast magnesium. Ball bearings support the input shaft, the front output shaft, as well as the rear output shaft. The input shaft delivers the power to the planetary differential. The case of the planetary differential is splined to the input shaft. The front sun gear is engaged with the drive sprocket, which drives the chain for the front output shaft, and power is sent to the front dtive shaft.

Potential problems with the BW4485 Transfer Case
This unit can have issues with case failure caused by out of balance rear driveshafts, at the first sign of vibration it is time to get the driveline inspected, repaired and high speed balanced before case failure. High mileage will contribute to failure of the range hub, range fork and input shaft, this failure is exhibited by the unit popping out of gear. Be sure that at each oil change you check the fluid level in the BW4485. Recommended fluid for the BW4485 transfer case is Dextron VI.

If you have purchased your Denali, Escalade, Sierra, Silverado 1500, Suburban & Yukon used the very first order of business is to double check the tire diameters and tire pressure. Used car dealers may have mismatched the tires to make the sale. Mismatched tires will cause the BW4485 transfer case to fail.
 

Campbesl

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Can a person change out the chain in the BW4485 without totally removing the TC from the vehicle? Specifically, can you remove the front drive shaft then remove the front cover and through that approach replace the chain?
 

Geotrash

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Can a person change out the chain in the BW4485 without totally removing the TC from the vehicle? Specifically, can you remove the front drive shaft then remove the front cover and through that approach replace the chain?
Possibly, but I don't know for sure. You can get a cheap transmission jack from horrible freight that will let you drop the thing out so you can rebuild it on the bench, if that helps.
 

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