GM Service Manual Online
For 1990-2009 cars only

DELAYED ENGAGEMENT 1ST GEAR GOV.HUB SEAL RINGS SEIZED/180C

SOME 1982 AND 1983 THM 180-C TRANSMISSIONS MAY EXPERIENCE DELAYED ENGAGEMENT IN FIRST GEAR. THIS CONDITION MAY BE THE GOVENOR HUB SEAL RINGS SEIZED IN THEIR GROOVES (FIGURE 1). WHEN SERVICING ANY 1982 OR 1983 THM 180-C TRANSMISSION WITH A DELAYED ENGAGEMENT CONDITION, REFER TO THE SERVICE PROCEDURE BELOW. SERVICE PROCEDURE: 1. CHECK ENGINE VACUUM USING A VACUUM GAGE TO INSURE THERE IS SUFFICIENT VACUUM TO THE TRANSMISSION. REFER TO YOUR SERVICE MANUAL FOR SPECIFICATIONS AND CORRECT AS REQUIRED. 2. CHECK THE MODULATOR TO INSURE THAT IT IS THE CORRECT PART NUMBER. REFER TO THE PARTS MANUAL FOR SPECIFIC PART NUMBERS. 3. CHECK FOR FREENESS OF THE GOVERNOR HUB SEAL RINGS. THE RINGS SHOULD ROTATE FREELY IN THE GROOVES. IF NOT, REMOVE THE RINGS, CLEAN THE GROOVES WITH CLEANING SOLVENT, AND INSPECT THE GOVENOR HUB RING GROOVES FOR NICKS OR BURRS. REMOVE ALL BURRS, IF ANY ARE PRESENT. REPLACE THE GOVERNOR HUB AND GOVERNOR HUB SEAL RINGS IF NECESSARY. REFER TO YOUR PARTS MANUAL FOR SPECIFIC PART NUMBERS. 4. CHECK THE BAND ADJUSTMENT PER SPECIFICATIONS OUTLINED IN YOUR SERVICE MANUAL. 5. CHECK THE THIRD SPEED CLUTCH INPUT SPRAG FOR WEAR. IF THE SPRAG IS WORN, REFER TO YOUR PARTS MANUAL AND REPLACE IT.


Object Number: 95025  Size: SH

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.