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Transfer Case - Bw 4476/79 Cadillac STS I

Transfer Case 5 illustrations ~1253 words

Fastener Tightening Specifications

ApplicationSpecification
MetricEnglish
Case Bolts22-27 N.m16-20 lb ft
Chain Snubber Bolts7 N.m62 lb in
Dampener Attaching Bolts27-35 N.m20-26 lb ft
Drain Plug19-30 N.m14-22 lb ft
Fill Plug19-30 N.m14-22 lb ft
Propeller Shaft-to-Transfer Case Flange Bolt30 N.m22 lb ft
Transfer Case-to-Transmission Bolts60 N.m44 lb ft
Transmission Mount-to-Body Bolt60 N.m44 lb ft
Transmission Mount-to-Transmission Bolt110 N.m81 lb ft
Vent Baffle7 N.m62 lb in

Fastener Tightening Specifications

Capacities - Approximate Fluid

ApplicationSpecification
MetricEnglish
DEXRON®III Fluid GM P/N 12346143 (Canadian P/N 10952622)500 ml0.53 quart

Capacities - Approximate Fluid

Sealers, Adhesives, and Lubricants

ApplicationType of MaterialGM Part Number
United StatesCanada
Chain Snubber BoltsThreadlocker1234538210953489
Drain PlugPipe Sealant1234600410953480
Fill PlugPipe Sealant1234600410953480
Front Output Shaft Cup PlugThreadlocker1234538210953489
Input Shaft Inside Diameter (ID)Lubricant1051344993037
Rear Case Half-to-Front Case HalfRTV Sealant1234573910953541
Thrust WasherTransjel LubricantJ 36850J 36850
Transfer Case FluidDEXRON®III1237847010952622
Vent Baffle BoltsThreadlocker1234538210953489

Sealers, Adhesives, and Lubricants

Diagnostic Starting Point - Transfer Case

Begin the system diagnosis by reviewing the Symptoms - Transfer Case . The Symptoms - Transfer Case will provide the following information

  1. The required visual/physical inspections
  2. The list of symptoms

Use the Strategy Based Diagnosis in General Information in order to identify the correct procedure for diagnosing the system.

Strategy Based Diagnostics

Review the system operation in order to familiarize yourself with the system functions. Refer to Transfer Case Description and Operation .

Visual/Physical Inspection

  1. Inspect the easily accessible or visible system components for obvious damage, or for conditions which could cause the symptom.
  2. Inspect the transfer case for the proper fluid. Refer to «Transfer Case Fluid Replacement»(/cadillac/sts/i-2004-2007/remont/transfer-case/#transfer-case-bw-447679) .

Symptom List

Refer to a symptom diagnostic procedure from the following list in order to diagnose the symptom

  1. «Transfer Case Popping Noise»(/cadillac/sts/i-2004-2007/remont/transfer-case/#transfer-case-bw-447679__transfer-case-popping-noise)
  2. «Transfer Case Whine or Rumble Noise»(/cadillac/sts/i-2004-2007/remont/transfer-case/#transfer-case-bw-447679__transfer-case-whine-or-rumble-noise)
  3. «Transfer Case Growl or Grinding Noise»(/cadillac/sts/i-2004-2007/remont/transfer-case/#transfer-case-bw-447679__transfer-case-growl-or-grinding-noise)
  4. «Transfer Case Shudder or Binding»(/cadillac/sts/i-2004-2007/remont/transfer-case/#transfer-case-bw-447679__transfer-case-shudder-or-binding)
  5. «Transfer Case Clunk during Acceleration and Deceleration»(/cadillac/sts/i-2004-2007/remont/transfer-case/#transfer-case-bw-447679__transfer-case-clunk-during-acceleration-and)
  6. «Transfer Case Leak Diagnosis»(/cadillac/sts/i-2004-2007/remont/transfer-case/#transfer-case-bw-447679__transfer-case-leak-diagnosis)

Transfer Case Popping Noise

CauseCorrection
DEFINITION: A faulty internal transfer case component that causes a popping noise in the transfer case. Review the Symptoms - Transfer Case and perform the necessary inspections.
Chain jumpReplace the chain and sprockets. Refer to TRANSFER CASE DISASSEMBLE and TRANSFER CASE ASSEMBLE in Transfer Case - Overhaul - BW 4476/79 - STS. Replace the shaft bearings. Refer to TRANSFER CASE DISASSEMBLE and TRANSFER CASE ASSEMBLE in Transfer Case - Overhaul - BW 4476/79 - STS. Inspect for damaged components caused by metal debris. Refer to TRANSFER CASE DISASSEMBLE and TRANSFER CASE ASSEMBLE in Transfer Case - Overhaul - BW 4476/79 - STS.

Transfer Case Popping Noise

Transfer Case Whine or Rumble Noise

CauseCorrection
DEFINITION: A faulty internal transfer case component that causes a whine noise in the transfer case. Review the Symptoms - Transfer Case and perform the necessary inspections.
Faulty bearingsInspect all of the bearings and journals. Refer to CLEANING AND INSPECTION in Transfer Case - Overhaul - BW 4476/79 - STS. Replace any faulty bearings, and any components with faulty bearing journals. Refer to TRANSFER CASE DISASSEMBLE and TRANSFER CASE ASSEMBLE in Transfer Case - Overhaul - BW 4476/79 - STS.
Worn or loose chainInspect for a loose chain, excessive wear on the snubber or deep gouges in the lining. Replace the chain, sprockets and snubber. Refer to TRANSFER CASE DISASSEMBLE and TRANSFER CASE ASSEMBLE in Transfer Case - Overhaul - BW 4476/79 - STS.

Transfer Case Whine or Rumble Noise

Transfer Case Growl or Grinding Noise

CauseCorrection
DEFINITION: A faulty internal transfer case component that causes a growl or grinding noise in the transfer case while the vehicle is turning. Review the Symptoms - Transfer Case and perform the necessary inspections.
Planetary differentialInspect the planetary differential pinion gears for the following conditions: Chipped, bent or deformed teeth Pinion gear bushings worn Pinion gear thrust washers missing Seized or binding pinion gears Refer to CLEANING AND INSPECTION in Transfer Case - Overhaul - BW 4476/79 - STS. Inspect the planetary differential for deformation. Refer to CLEANING AND INSPECTION in Transfer Case - Overhaul - BW 4476/79 - STS. Replace the planetary differential assembly if faulty. Refer to TRANSFER CASE DISASSEMBLE and TRANSFER CASE ASSEMBLE in Transfer Case - Overhaul - BW 4476/79 - STS.
Sun gearsInspect the sun gears for the following conditions: Gear tooth failure Worn or galled thrust surfaces Refer to CLEANING AND INSPECTION in Transfer Case - Overhaul - BW 4476/79 - STS. Replace the sun gears if faulty. Refer to TRANSFER CASE DISASSEMBLE and TRANSFER CASE ASSEMBLE in Transfer Case - Overhaul - BW 4476/79 - STS.
Thrust washerInspect the thrust washer for seizure to the planetary differential. Inspect the thrust washer for galling. Replace the thrust washer if faulty and the mating component if damaged. Refer to TRANSFER CASE DISASSEMBLE and TRANSFER CASE ASSEMBLE in Transfer Case - Overhaul - BW 4476/79 - STS.
Planetary differential not timed properlyInspect the planetary differential for being timed properly. Refer to TRANSFER CASE ASSEMBLE in Transfer Case - Overhaul - BW 4476/79 - STS. Properly time the planetary differential gears. Refer to TRANSFER CASE ASSEMBLE in Transfer Case - Overhaul - BW 4476/79 - STS.

Transfer Case Growl or Grinding Noise

Transfer Case Shudder or Binding

CauseCorrection
DEFINITION: A shudder, binding, or a crop-hop while turning, which may cause tire scuffing. Review the Symptoms - Transfer Case and perform the necessary inspections.
Planetary differentialInspect the planetary differential pinion gears for the following conditions: Chipped, bent or deformed teeth Pinion gear bushings worn Pinion gear thrust washers missing Seized or binding pinion gears Refer to CLEANING AND INSPECTION in Transfer Case - Overhaul - BW 4476/79 - STS. Inspect the planetary differential for deformation. Refer to CLEANING AND INSPECTION in Transfer Case - Overhaul - BW 4476/79 - STS. Replace the planetary differential assembly if faulty. Refer to TRANSFER CASE DISASSEMBLE and TRANSFER CASE ASSEMBLE in Transfer Case - Overhaul - BW 4476/79 - STS.
Thrust washerInspect the thrust washer for seizure to the planetary differential. Replace the thrust washer if faulty and the mating component if damaged. Refer to TRANSFER CASE DISASSEMBLE and TRANSFER CASE ASSEMBLE in Transfer Case - Overhaul - BW 4476/79 - STS.
Planetary differential not timed properlyInspect the planetary differential for being timed properly. Refer to TRANSFER CASE ASSEMBLE in Transfer Case - Overhaul - BW 4476/79 - STS. Properly time the planetary differential gears. Refer to TRANSFER CASE ASSEMBLE in Transfer Case - Overhaul - BW 4476/79 - STS.

Transfer Case Shudder or Binding

Transfer Case Clunk during Acceleration and Deceleration

CauseCorrection
DEFINITION: During acceleration or deceleration, a clunk is heard or felt in the transfer case. Review the Symptoms - Transfer Case and perform the necessary inspections.
Incorrect fluid level or incorrect fluidInspect the transfer case for the correct fluid level. Refer to Transfer Case Fluid Replacement . Inspect the transfer case for the correct type of fluid. Flush the transfer case, and fill with the correct fluid, if required. Refer to Capacities - Approximate Fluid .
Worn or faulty planetary differentialInspect the planetary differential for the following conditions: Loose planetary differential splines to the input shaft splines Loose or faulty pinion gears Refer to CLEANING AND INSPECTION in Transfer Case - Overhaul - BW 4476/79 - STS. Replace the planetary differential assembly if faulty. Refer to TRANSFER CASE DISASSEMBLE and TRANSFER CASE ASSEMBLE in Transfer Case - Overhaul - BW 4476/79 - STS.
Worn or missing sun gear thrust washerInspect to ensure the thrust washer is installed. Inspect the thrust washer and mating surface for excessive wear. Replace the worn or missing thrust washer. Refer to TRANSFER CASE DISASSEMBLE and TRANSFER CASE ASSEMBLE in Transfer Case - Overhaul - BW 4476/79 - STS.
Worn or damaged rear sun gearInspect the sun gear external gear teeth for excessive wear. Inspect the sun gear-to-rear output shaft for excessive looseness. Replace the sun gear or rear output shaft if worn. Refer to TRANSFER CASE DISASSEMBLE and TRANSFER CASE ASSEMBLE in Transfer Case - Overhaul - BW 4476/79 - STS.
Rear output shaft bearing outer retaining ringInspect for the following conditions: Proper installation of the rear output shaft bearing retaining ring Excessive wear or damaged retaining ring groove in the rear case half Repair or replace the following components if found faulty: Properly install a new rear output shaft bearing outer retaining ring. Replace the rear case half if the retaining ring groove is excessively worn. Refer to TRANSFER CASE DISASSEMBLE and TRANSFER CASE ASSEMBLE in Transfer Case - Overhaul - BW 4476/79 - STS.
Worn or loose chainInspect for a loose chain, excessive wear on the snubber or deep gouges in the lining. Replace the chain, sprockets and snubber. Refer to TRANSFER CASE DISASSEMBLE and TRANSFER CASE ASSEMBLE in Transfer Case - Overhaul - BW 4476/79 - STS.

Transfer Case Clunk during Acceleration and Deceleration

Transfer Case Leak Diagnosis

CauseCorrection
DEFINITION: A visible indication of an external fluid leak from the transfer case. Review the Symptoms - Transfer Case and perform the necessary inspections.
Drain plug or fill plug leakInspect for the correct sealer and the correct amount of sealer on the plugs. Install the plugs correctly. Refer to Transfer Case Fluid Replacement .
Rear output shaft seal leakingInspect for the following conditions: Overfilled or improper transfer case fluid Blocked vent Seal improperly installed, worn, or damaged Seal bore damaged or cracked Repair or replace the following components if found faulty: Adjust or replace the transfer case fluid. Refer to Transfer Case Fluid Replacement . Replace the rear case half if the bushing is worn. Refer to TRANSFER CASE DISASSEMBLE and TRANSFER CASE ASSEMBLE in Transfer Case - Overhaul - BW 4476/79 - STS. Replace the rear case half if the seal bore is damaged. Refer to TRANSFER CASE DISASSEMBLE and TRANSFER CASE ASSEMBLE in Transfer Case - Overhaul - BW 4476/79 - STS. Replace the rear output shaft seal. Refer to TRANSFER CASE DISASSEMBLE and TRANSFER CASE ASSEMBLE in Transfer Case - Overhaul - BW 4476/79 - STS.
Front output shaft seal leakingInspect for the following conditions: Overfilled or improper transfer case fluid Blocked vent Seal improperly installed, worn, or damaged Seal bore damaged or cracked Repair or replace the following components if found faulty: Adjust or replace the transfer case fluid. Refer to Transfer Case Fluid Replacement . Replace the front case half if the seal bore is damaged. Refer to TRANSFER CASE DISASSEMBLE and TRANSFER CASE ASSEMBLE in Transfer Case - Overhaul - BW 4476/79 - STS. Replace the front output shaft seal. Refer to TRANSFER CASE DISASSEMBLE and TRANSFER CASE ASSEMBLE in Transfer Case - Overhaul - BW 4476/79 - STS.
Leaking at the ventLeaking vent or input seal will be noticed from a weep hole between the adapter and the transfer case. Transfer case overfilled Inspect for the correct transfer case fluid level. Refer to Transfer Case Fluid Replacement . Damaged O-ring on vent Transmission output shaft seal leak will be noticed from a weep hole between the adapter and the transfer case.
Transfer case-to-adapter leakInspect for the following conditions: Loose mounting fasteners Gasket or sealant faulty The transfer case input shaft seal leaking Damaged O-ring on vent Repair or replace the following components if found faulty: Replace the transfer case input shaft seal. Refer to Transfer Case Input Shaft Seal Replacement . Inspect for the following: Seal improperly installed, worn, or damaged Seal bore damaged or cracked Input shaft seal surface worn, grooved, or damaged Repair or replace the loose fasteners. Replace the transfer case gasket or sealer. Repair or replace the following components if found faulty: Leaking transmission output seal Remove transfer case. Refer to Transfer Case Assembly Replacement . Leaking adapter gasket and seal Replace adapter gasket and seal. Refer to Extension Housing and Seal Replacement in Automatic Transmission - 5L40-E/5L50-E.
Front case half-to-rear case half seam leakDisassemble and seal the case halves. Refer to TRANSFER CASE DISASSEMBLE and TRANSFER CASE ASSEMBLE in Transfer Case - Overhaul - BW 4476/79 - STS.
Case leakingInspect for a cracked case or case porosity. Replace the faulty case half. Refer to TRANSFER CASE DISASSEMBLE and TRANSFER CASE ASSEMBLE in Transfer Case - Overhaul - BW 4476/79 - STS.

Transfer Case Leak Diagnosis

Removal Procedure

IMPORTANTWhen performing the following procedure, use only hand tools to remove and install the drain and fill plugs.
  1. Raise and suitably support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/cadillac/sts/i-2004-2007/remont/hoistjack/#general-information) 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»(/cadillac/sts/i-2004-2007/remont/transfer-case/#transfer-case-bw-447679) .
  2. Remove the exhaust system. Refer to «Exhaust System Replacement»(/cadillac/sts/i-2004-2007/remont/exhaust/#engine-exhaust-system__exhaust-system-replacement) in Engine Exhaust.
  3. Remove the rear propeller shaft. Refer to «Propeller Shaft Replacement - Rear (AWD)»(/cadillac/sts/i-2004-2007/remont/driveshaft-universal-joints/#propeller-shaft-and-universal-joints__propeller-shaft-replacement-rear-awd) or «Propeller Shaft Replacement - Rear (RWD)»(/cadillac/sts/i-2004-2007/remont/driveshaft-universal-joints/#propeller-shaft-and-universal-joints__propeller-shaft-replacement-rear-rwd) 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.
IMPORTANTThe front propeller shaft must be lines up with the front output shaft at the same time that the input is being slid onto the transmission output shaft and the dowel pins are engaged. The front propeller shaft is too long and can not be installed after the transfer case mounting face is bolted in place to the transmission. The transfer case needs to be loose and slid back slightly so that the cone shape of the constant velocity (CV) joint can be engaged into the front output shaft.
  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»(/cadillac/sts/i-2004-2007/remont/oem-general-information/#cautions-and-notices__fastener-notice) 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)»(/cadillac/sts/i-2004-2007/remont/driveshaft-universal-joints/#propeller-shaft-and-universal-joints__propeller-shaft-replacement-rear-awd) or «Propeller Shaft Replacement - Rear (RWD)»(/cadillac/sts/i-2004-2007/remont/driveshaft-universal-joints/#propeller-shaft-and-universal-joints__propeller-shaft-replacement-rear-rwd) in Propeller Shaft.
  15. Install the exhaust system. Refer to «Exhaust System Replacement»(/cadillac/sts/i-2004-2007/remont/exhaust/#engine-exhaust-system__exhaust-system-replacement) in Engine Exhaust.
  16. Refill the transfer case with fluid. Refer to «Transfer Case Fluid Replacement»(/cadillac/sts/i-2004-2007/remont/transfer-case/#transfer-case-bw-447679) .

Transfer Case Input Shaft Seal Replacement

Tools Required

  1. J 8092 Driver Handle
  2. J 23907 Slide Hammer with Bearing Adapter. See «Special Tools»(/cadillac/sts/i-2004-2007/remont/transfer-case/#transfer-case-bw-447679__special-tools) .
  3. J 45278 Seal Remover. See «Special Tools»(/cadillac/sts/i-2004-2007/remont/transfer-case/#transfer-case-bw-447679__special-tools) .
  4. J 46269 Input Seal Installer. See «Special Tools»(/cadillac/sts/i-2004-2007/remont/transfer-case/#transfer-case-bw-447679__special-tools) .
  1. Remove the transfer case. Refer to «Transfer Case Assembly Replacement»(/cadillac/sts/i-2004-2007/remont/transfer-case/#transfer-case-bw-447679) .
  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»(/cadillac/sts/i-2004-2007/remont/transfer-case/#transfer-case-bw-447679__special-tools) . 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»(/cadillac/sts/i-2004-2007/remont/transfer-case/#transfer-case-bw-447679__special-tools) .
  5. Install the transfer case. Refer to «Transfer Case Assembly Replacement»(/cadillac/sts/i-2004-2007/remont/transfer-case/#transfer-case-bw-447679) .

Scheme 1

Scheme 1: Transfer Case Description and Operation
Scheme 1: Transfer Case Description and Operation

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.

Special Tools

Special Tools Illustration Tool Number/Description J 8092 Driver Handle J 23907 Slide Hammer with Bearing Adapter J 45278 Seal Remover J 46269 Input Seal Installer

Scheme 2

Scheme 2: Special Tools
Scheme 2: Special Tools

Scheme 3

Scheme 3
Scheme 3

Scheme 4

Scheme 4
Scheme 4

Scheme 5

Scheme 5
Scheme 5

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