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According to the information i looked up your transfer case is a NR3 1-speed full time AWD. I'll give you the description and operation below for you.
Transfer Case Description and Operation
The Borg Warner (BW) model 4485, RPO NR3 transfer case is a 1-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 2 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:
The BW 4485 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.
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They must have meant the RPO code for the vehicle which is NR3. If you look at the vin number the fifth number is XXXXX a C or a K. The letter C means that it's a 2wd and a K means it's a 4wd or a awd in your case.
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