Transfer Case - Bw 4476/79: Removal & Installation Cadillac STS I

Removal Procedure

1. Raise and suitably support the vehicle. Refer to «Lifting and Jacking the Vehicle»(ref-197567-S01952905382005101200000) in General Information.
2. Remove the fill plug (6).
3. Remove the drain plug (8).
4. Allow the transfer case to drain completely.

Installation Procedure

1. Apply sealant GM P/N 12346004, (Canadian P/N 10953480), or equivalent to the threads of the drain plug.
2. Install the drain plug (8). Tighten: Tighten the drain plug to 25 N.m (18 lb ft).
3. Fill the transfer case to the bottom of the fill plug hole with DEXRON®-III, GM P/N 12346143, (Canadian P/N 10952622).
4. Install the fill plug (6). Tighten: Tighten the fill plug to 25 N.m (18 lb ft).
5. Lower the vehicle.

1. Drain the transfer case fluid. Refer to «Transfer Case Fluid Replacement»(ref-197622-S03812431152005101200000) .
2. Remove the exhaust system. Refer to «Exhaust System Replacement»(ref-197578-S11696311262005101200000) in Engine Exhaust.
3. Remove the rear propeller shaft. Refer to «Propeller Shaft Replacement - Rear (AWD)»(ref-197579-S22039518262005101200000) or «Propeller Shaft Replacement - Rear (RWD)»(ref-197579-S26284065052005101200000) in Propeller Shaft.
4. Support the transmission with a suitable jack and a block of wood.
5. Remove the transmission mount-to-body bolts.
6. Remove the transmission mount-to-transmission bolts.
7. Remove the transmission mount.
8. Install a flat-bladed tool into the notch on the transfer case flange.
9. Using the flat-bladed tool, carefully move the propeller shaft toward the front of the vehicle and remove the propeller shaft from the transfer case flange.
10. Using mechanics wire, tie the front propeller shaft up and out of the way.
11. Using a suitable adjustable jack, support the transfer case.
12. Remove the transfer case bolts.
13. Remove the transfer case.

1. Apply grease GM P/N 1051344 (Canadian P/N 993037), or equivalent, on the input splines starting from the front edge to 10 mm inward in a continuous pattern around the inside diameter (ID) of the splines to completely fill the splines.
2. Install the transfer case. NOTE: Refer to «Fastener Notice»(ref-197542-S12062241132005101200000) in Cautions and Notices.
3. Install the transfer case-to-transmission bolts. Tighten: Tighten the case-to-transmission bolts to 60 N.m (44 lb ft).
4. Remove the support from the transfer case.
5. Untie the front propeller shaft and position to the transfer case.
6. Install the propeller shaft to the transfer case flange.
7. Inspect the propeller shaft to flange bolts. Replace if damaged or worn.
8. Thoroughly clean the threads using denatured alcohol or equivalent and allow to dry. Apply threadlock GM P/N 12345493 (Canadian P/N 10953488), or equivalent, to the propeller shaft to flange bolts. Ensure that there are no gaps in the threadlock along the length of the filled area of the bolt. Allow the threadlock to cure approximately 10 minutes prior to installation.
9. Install the propeller shaft to transfer case flange bolts. Ensure that the crescent washers are in place on each pair of bolts. Tighten: Tighten the bolts in sequence to 30 N.m (22 lb ft).
10. Install the transmission mount.
11. Install the transmission mount-to-transmission bolts. Tighten: Tighten the mount-to-transmission bolts 110 N.m (81 lb ft).
12. Install the transmission mount-to-body bolts. Tighten: Tighten the mount-to-body bolts to 60 N.m (44 lb ft).
13. Remove the support from the transmission.
14. Install the rear propeller shaft. Refer to «Propeller Shaft Replacement - Rear (AWD)»(ref-197579-S22039518262005101200000) or «Propeller Shaft Replacement - Rear (RWD)»(ref-197579-S26284065052005101200000) in Propeller Shaft.
15. Install the exhaust system. Refer to «Exhaust System Replacement»(ref-197578-S11696311262005101200000) in Engine Exhaust.
16. Refill the transfer case with fluid. Refer to «Transfer Case Fluid Replacement»(ref-197622-S03812431152005101200000) .

Transfer Case Input Shaft Seal Replacement

Tools Required

1. J 8092 Driver Handle
2. J 23907 Slide Hammer with Bearing Adapter. See «Special Tools»(ref-197622-S11203287022005101200000) .
3. J 45278 Seal Remover. See «Special Tools»(ref-197622-S11203287022005101200000) .
4. J 46269 Input Seal Installer. See «Special Tools»(ref-197622-S11203287022005101200000) .

1. Remove the transfer case. Refer to «Transfer Case Assembly Replacement»(ref-197622-S29699578102005101200000) .
2. Using J 45278 (2) and J 23907 (1), slide the hook end of J 45278 beside the seal lip and shaft. See «Special Tools»(ref-197622-S11203287022005101200000) . Turn the hook about 60 degrees and pull the seal out with the slide hammer.
3. Clean the seal area (1) and input shaft of any old seal material with solvent.
4. Use J 8092 (1) and J 46269 (2) to drive in a NEW input seal. See «Special Tools»(ref-197622-S11203287022005101200000) .
5. Install the transfer case. Refer to «Transfer Case Assembly Replacement»(ref-197622-S29699578102005101200000) .

Scheme 1

The Borg Warner (BW) model 4479, 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 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 BW 4479 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.

Reduced driveline backlash is achieved through press fit interfaces of the lower sprocket, sun gear, and input shaft assembly.

The BW 4479 case halves are high-pressure, die-cast aluminum. Ball bearings support the input shaft, the front output shaft, and the rear output shaft. The transfer case requires DEXRON®III ATF Fluid GM P/N 12346143 (Canadian P/N 10952622), which is red in color.