SERVICE MANUAL UPDATE SEC. 4B 4C, 4D1 & 4D2/PINION BEARINGS

SUBJECT: SERVICE MANUAL UPDATE SECTIONS 4B,4C,4D1 AND 4D2 PINION BEARING PRELOAD ADJUSTMENT

VEHICLES AFFECTED: 1989-92 GEO 'E/J' TRACKER

This bulletin cancels and supersedes the "Pinion Bearing Preload" adjustment procedure found on pages 4D-14 of the 1989 Geo Tracker Service Manual, pages 4D1-l9 and 4D2-8 of the 1990 Geo Tracker Service Manual, pages 4D1-9 and 4D2-9 of the 1991 Geo Tracker Service Manual, and pages 4B-35, 4B-41, 4C-35 and 4C-41 of the 1992 Geo Tracker Service Manual. Refer to this bulletin for information concerning pinion bearing preload adjustment procedures.

IMPORTANT: Use caution not to overtighten the pinion flange nut when adjusting pinion bearing preload. Tighten the pinion flange nut gradually while taking frequent pinion bearing preload measurements with a torque wrench. If the pinion flange nut is overtightened, the collapsible spacer will crush, requiring a new collapsible spacer before pinion bearing preload can be properly adjusted.

Tool Requirement:

J 8614-01 Flange Holder

Adjust: Pinion bearing preload using a J 8614-01 to hold the pinion flange stationary while tightening the pinion flange nut. Tighten the nut gradually in increments of 5 N.m (44 In.Lbs.). Between each increment of tightening, remove the J 8614-01, rotate the pinion gear five (5) revolutions in order to ensure pinion bearing seating and measure pinion bearing preload.

Measure: Pinion bearing preload using a torque wrench. The pinion gear should require 1.2 N.m (11 In.Lbs.) of torque in order to rotate. If pinion bearing preload is less than specified, repeat the adjustment procedure until the proper pinion bearing preload has been attained.

Stake the pinion flange nut.

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.