REAR AXLE USEAGE AND SPECS 1984 LIMO/COMMERCIAL

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-.23mm .005-.009 in. Lash must not vary over.05mm (.002 in) around ring gear Pinion Depth .50 to 1.27mm .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-21777-4 3 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 tbe appropriate 7 1/2 inch labor Operation Number from the 1984 Labor Time Guide.

General Motors bulletins are intended for use by professional technicians, not a "do-it-yourselfer". They are written to inform those technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions and know-how to do a job properly and safely. If a condition is described, do not assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See a General Motors dealer servicing your brand of General Motors vehicle for information on whether your vehicle may benefit from the information.