Transfer Case - Overhaul - Borg-Warner 4472 GMC Sonoma Syclone

IDENTIFICATION

An aluminum identification tag is attached under a self-tapping case bolts at bottom of transfer case. This tag provides part number, serial number and build date.

DESCRIPTION

The Borg-Warner Model 4472 transfer case is a full-time All-Wheel Drive (AWD) unit. It is chain-driven and has a 3-piece aluminum case. Torque distribution is by viscous clutch. Torque is divided at a ratio of 1:3 to the front and 2:3 to the rear.

Removal

Raise vehicle, and disconnect front and/or rear drive shaft. Remove front output shaft flange nut and steel flat washer. Remove rubber sealing washer and front output flange. Pry out output shaft oil seals using screwdriver. DO NOT damage seal bore.

Installation

1. Lubricate seals with ATF. Install front oil seal using Output Shaft Seal Installer (J-37668). Install rear oil seal by aligning water drain hole in output shaft oil seal with drain groove in extension housing.
2. Install front output shaft flange and rubber sealing washer. Install steel flat washer and flange nut. Tighten nut to specification. See «TORQUE SPECIFICATIONS»(/gmc/sonoma-syclone/1991-1992/remont/transfer-case/#transfer-case-overhaul-borg-warner-4472__torque-specifications) . Reconnect drive shafts, and check fluid level.

Removal & Installation

1. Raise vehicle, and drain transfer case. Remove skid plate and heat shield. Remove front and rear drive shafts. Disconnect breather hose and electrical connections at transfer case.
2. Support transfer case with suitable jack. Remove transfer case support brace and adapter-to-transfer case bolts. Remove transfer case mount nuts and washers.
3. To install, reverse removal procedures. Ensure mating surfaces are clean, and install new gasket. Tighten bolts and nuts to specification. See «TORQUE SPECIFICATIONS»(/gmc/sonoma-syclone/1991-1992/remont/transfer-case/#transfer-case-overhaul-borg-warner-4472__torque-specifications) .

Disassembly

1. Remove front output flange nut. Remove steel flat washer, rubber sealing washer and output flange from front output shaft. Remove speed sensor bolt and speed sensor from extension housing. (Scheme 12)
2. Remove front cover bolts from rear case half, and remove front cover by prying case tabs apart. Remove front output shaft, drive chain and driven sprocket from rear case half. Remove input shaft from sun gear shaft.
3. Remove, as an assembly, sun gear shaft, sun gear shaft bearing, drive sprocket spacer, drive sprocket, viscous clutch and sun gear shaft thrust washer from planet carrier assembly. Remove planet carrier assembly and thrust washer from output shaft assembly.
4. Remove extension housing bolts and breather assembly from extension housing. Remove extension housing from rear case half. Remove output shaft snap ring from output shaft bearing.
5. Remove gear ring snap ring and output shaft assembly from gear ring. Remove front output shaft oil seal, input shaft oil seal, output shaft bearing snap ring and output shaft bearing from front cover. Remove rear output shaft oil seal from extension housing.
6. Press sun gear shaft bearing from sun gear shaft. Remove drive sprocket spacer, drive sprocket and viscous clutch from sun gear shaft.
7. Remove input shaft pilot bearing from output shaft assembly. Remove output shaft rear bearing from rear case half.

Scheme 12

Cleaning & Inspection

Clean all parts with solvent and dry with compressed air. Replace all oil seals, "O" rings and snap rings. Check all parts for wear or damage. Replace all worn or damaged parts.

Note. Apply ATF to all parts before installing.

Reassembly

1. Install viscous clutch, drive sprocket, drive sprocket spacer and sun gear shaft bearing onto sun gear shaft. Install input shaft pilot bearing into output shaft assembly. Install output shaft assembly to gear ring, and install gear ring snap ring.
2. Install front output shaft bearing and bearing snap ring to front cover. Install rear output shaft bearing to rear case half.
3. Install output shaft assembly and gear ring through rear case half. Install output shaft bearing snap ring to output bearing. Apply an 1/8" bead of RTV silicone to rear case half extension housing sealing surface.
4. Install extension housing and bolts to rear case half. Tighten bolts to specification. Install speed sensor and speed sensor bolt into extension housing. Tighten to specification. See «TORQUE SPECIFICATIONS»(/gmc/sonoma-syclone/1991-1992/remont/transfer-case/#transfer-case-overhaul-borg-warner-4472__torque-specifications) .
5. Align water drain hole in rear output shaft oil seal with drain groove in extension housing, and press seal into extension housing.
6. Using petroleum jelly, install planet carrier assembly thrust washer to output shaft assembly and align with input shaft pilot bearing. Install planet carrier assembly into gear ring. Install sun gear shaft thrust washer to planet carrier assembly.
7. Install sun gear shaft assembly into planet carrier assembly planet gears, and align viscous clutch teeth with gear ring spline. Install input shaft into input shaft pilot bearing, aligning input shaft with sun gear shaft thrust washer and planet carrier assembly thrust washer.
8. Install driven sprocket onto front output shaft, and install drive chain onto driven sprocket. Install drive chain over drive sprocket, and install front output shaft into output shaft rear bearing. Install front output shaft spacer and magnet.
9. Apply 1/8" bead of RTV silicone to rear case half front cover sealing surface. Install front cover and bolts to rear case. Tighten bolts to specification. See «TORQUE SPECIFICATIONS»(/gmc/sonoma-syclone/1991-1992/remont/transfer-case/#transfer-case-overhaul-borg-warner-4472__torque-specifications) .
10. Install front output shaft oil seal and input shaft oil seal. Install front output flange, rubber washer, steel flat washer and a new front output flange nut. Tighten flange nut to specification.

TORQUE SPECIFICATIONS

TORQUE SPECIFICATIONS

See also:
• TORQUE SPECIFICATIONS