Rear Differential - Service
Bulletin No. T 84-74File In Group 4B
Number 4
Date May '84
SUBJECT: LIMOUSINE AND COMMERCIAL CHASSIS 8 1/2 INCH REAR AXLE SERVICE PROCEDURES
MODELS AFFECTED: 1984 LIMOUSINE AND COMMERCIAL CHASSIS
I. 1984 Limousine
Effective with B.C. #112602, the 1984 model year Cadillac Limousine will begin using the limited slip version of the 8-7/8 inch 3:08:1 rear axle assembly in place of the conventional 8-7/8 inch 3:08:1 rear axle assembly. The rear axle code will be "XY" and is stamped on the right axle tube on the forward side. When servicing the 8-7/8 limited slip rear axle assembly, refer to the 1982 Service Information Manual, Section 4B, Rear Axle. This section of the Service Information Manual has been written for the 8-7/8 inch rear axle.
II. 1984 Commercial Chassis
Effective with B.C. #113293, the 1984 model year Cadillac Commercial Chassis will begin using an 8-1/2 inch, 3:08:1 ratio rear axle assembly. The rear axle code will be "MF" and will also be stamped in the right axle tube on the forward side.
When servicing the 8-1/2 inch rear axle assembly, refer to the 1982 Service Information Manual, Section 4B, Rear Axle, for service procedures only. The specifications which should be used for the 8-1/2 inch rear axle are as follows:
8-1/2 INCH TORQUE SPECIFICATIONS
Bearing Cap Bolts 75 N-m 55 ft.lbs.
Carrier Cover Bolts 27 N-m 20 ft.lbs.
Pinion Shaft Lock Screw 27 N-m 20 ft.lbs.
Strap Bolts 21 N-m 16 ft.lbs.
Pinion Bearing Pre-Load
New Bearings 2.26 - 2.82 N-m 20-25 in.lbs.
Used Bearings 1.13 - 1.69 N-m 10-15 in.lbs.
Total Assembly Pre-Load (measured at pinion flange nut)
*New Bearings 3.95 - 4.52 N-m 35-40 in.lbs.
*Reused Bearings 2.26 - 2.82 N-m 20-25 in.lbs.
Pinion Depth Measurement
Gage Plate Assembly Nut 1.6 - 2.2 N-m 15-25 in.lbs.
*Rotating Torque With New Seal - Ring Gear
8-1/2 INCH MEASUREMENTS
Ring Gear Position Backlash .13 - .23 mm .005-.009 in.
Lash must not vary over .05 mm (.002 in.) around ring gear
Pinion Depth .50 - 1.27 mm .020-.050 in.
The following is a list of special tools, previously supplied for servicing 7-1/2 inch and 8-7/8 inch axle assemblies, required for servicing the 8-1/2 inch rear axle. There are no new special tools required for servicing the 8-1/2 inch rear axle.
TOOL NAME TOOL NUMBER AXLE FURNISHED FOR
8-1/2 INCH 7-1/2 8-7/8
Slide Hammer Assembly J-2619 X
Slide Hammer Adapter J-2619-4 X
Holding Fixture J-3289-01 X
Base Assembly J-3289-20 X
Front Pinion Bearing Installer J-6133-01 X
Rear Pinion Bearing Installer J-6547 X
Side Bearing Shim Installer BT-6624 x
Wheel Stud Remover J-6627 X
Dial Indicator Plunger Extension J-7057 X
Dial Indicator Assembly J-8001 X
Driver Handle J-8092 X
Side Bearing Puller Adapter J-8107-4 X
Rear Pinion Bearing Race Installer J-8608 X
Axle Bearing Installer J-23765 X
Front Bearing Race Installer J-8611-01 X
Rear Pinion Bearing Remover J-8612-01 X
Pinion Flange Remover J-8614-02 X
Pinion Flange Remover Screw J-8614-03 X
Pinion Flange Holder J-8614-10 X
Axle Shaft Seal Installer J-23771 X
Gage Shaft and Pin Assembly J-21777-1 X
Pinion Gage Plate J-21777-2 or X
J-21777-29
Pinion Setting Gage Shaft Discs J-21777-3 or X
J-21777-45
Pinion Setting Gage Pilot Washer
(Front) J-21777-42 X
(Rear) J-21777-55 X
Pinion Setting Gage J-21777-43 X
Side Bearing Installer J-22175 X
Pinion Seal Installer J-22388 X
Pinion Holding Tool J-22535-1-2-3 X
Pinion Driver J-22536 X
Case Side Bearing Puller J-22888 X
Case Remover Attaching Bolts J-22962 X
Axle Shaft Bearing and Seal Remover J-22813-01 X
Axle Shaft Bearing Installer J-23765 X
Parts information for the 8-1/2 rear axle assembly will be available in the May, 1984 revision of the GMWDD Parts and Illustration Catalog.
When servicing the 8-1/2 inch rear axle assembly under warranty, use the appropriate 7-1/2 inch Labor Operation Number from the 1984 Labor Time Guide.