NEW 2-4 SERVO COVER AND SEAL SERVICE INFORMATION

BEGINNING APRIL, 1983 ALL THM 700 R4 TRANSMISSIONS WERE BUILT WITH A NEW 2-4 SERVO COVER AND SEAL. THIS CHANGE PROVIDES A TIGHTER SEAL FIT BETWEEN THE CASE SERVO BORE AND THE 2-4 SERVO COVER. THE NEW SERVO COVER "O"RING PART NUMBER 8647351 IS IDENTIFIED WITH A GREEN STRIPE . THIS IS TO DISTINGUISH IT FROM THE PAST "O"RING PART NUMBER 8642112 WHICH IS STILL USED ON THE SECOND APPLY PISTION. REFER TO FIGURE 2, NUMBERS 14 AND 21 FOR CORRECT LOCATION OF "O"RINGS. NOTE: THE PAST SERVO "O"RING PART NUMBER 8642112 CANNOT BE USED WITH THE NEW SERVO COVER, IF USED TOGETHER THEY WILL LEAK. SERVICE INFORMATION: IF A LEAK IS FOUND AT THE 2-4 SERVO COVER--- 1. REMOVE THE 2-4 SERVO COVER AND "O" RING SEAL. 2. CHECK THE CASE SERVO BORE FOR SHARP EDGES ESPECIALLY AT THE RECESSED SLOTS. SEE FIGURE 1. REMOVE ANY SHARP EDGES WITH A FILE. 3. CHECK THE CASE SERVO BORE FOR BURRS, NICKS OR DAMAGE ON SEALING WALL. IF DAMAGE IS FOUND REPLACE THE CASE. 4. CHECK THE 2-4 SERVO COVER FOR POROSITY OR DAMAGE. REPLACE WITH PART NUMBER 8642979 IF REQUIRED -- THIS PACKAGE WILL CONTAIN A NEW DESIGN 2-4 SERVO COVER AND "O" RING SEAL. 5. IF IT IS NECESSARY TO REPLACE ONLY THE "O" RING SEAL, USE PART NUMBER 8647351. 6. WHEN INSTALLING THE 2-4 SERVO COVER AND "O" RING SEAL, LUBRICATE THE SEAL WITH PETROLATUM OR EQUIVALENT AND USE CARE NOT TO CUT THE SEAL DURING INSTALLATION. (SEE ILLUSTRATIONS)

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.