DELAYED OR NO ENGINE BRAKING IN D3 (REPL. FORW.. Cadillac Seville 1998

SUBJECT: DELAYED OR NO ENGINE BRAKING IN D3 (REPLACE FORWARD AND COAST CLUTCH PISTON ASSEMBLIES)

MODELS: 1998 CADILLAC DEVILLE, ELDORADO, SEVILLE 1998 OLDSMOBILE AURORA BUILT PRIOR TO OCTOBER 24, 1997 - WITH HYDRA-MATIC 4T80-E TRANSAXLE (RPO MH1) AND 4.0L OR 4.6L ENGINE (VINS C, Y, 9 - RPOS L47, LD8, L37)

CONDITION: (SEE FIGURE 1) SOME OWNERS OF THE ABOVE 1998 MODEL TRANSAXLES BUILT PRIOR TO OCTOBER 24, 1997 (JULIAN DATE 297) MAY COMMENT ON A NO ENGINE BRAKING CONDITION OR A SEVERAL SECOND DELAY WHEN THE SHIFT LEVER IS PLACED IN THE D3 POSITION.

CAUSE: (SEE FIGURE 2) THIS CONDITION MAY BE THE RESULT OF COAST CLUTCH APPLY FLUID BEING RESTRICTED WITHIN THE FORWARD CLUTCH PISTON ASSEMBLY (807), WHICH IS THE HOUSING FOR THE COAST CLUTCH PISTON (810). COAST CLUTCH PISTON APPLY DOES NOT OCCUR DUE TO THIS FLUID RESTRICTION.

CORRECTION: (SEE FIGURE 3) TO REPAIR THIS CONDITION, A REVISED FORWARD CLUTCH PISTON ASSEMBLY (807) MUST BE INSTALLED. THE REVISION TO THE FORWARD CLUTCH PISTON IS AN ADDITIONAL MACHINING OPERATION ON THE COAST CLUTCH PISTON SIDE THAT APPEARS AS A SHINY SURFACE AT THE CENTER HUB OF THE FORWARD CLUTCH PISTON.

TRANSAXLES BUILT PRIOR TO OCTOBER 24, 1997 (JULIAN DATE 297) WILL BE SERVICED WITH A SERVICE KIT P/N 24213271 THAT CONTAINS BOTH THE NEW FORWARD CLUTCH PISTON (807) AND THE COAST CLUTCH PISTON (810). BOTH PISTONS MUST BE REPLACED TOGETHER TO ENSURE THAT COAST CLUTCH FLUID IS NO LONGER RESTRICTED.

SERVICE INFORMATION - ROAD TEST THE VEHICLE AND VERIFY THAT IT HAS NO ENGINE BRAKING IN D3 AS DESCRIBED UNDER "CONDITION". REPLACE THE FORWARD CLUTCH PISTON ASSEMBLY. REFER TO THE UNIT REPAIR SECTION OF THE SERVICE MANUAL FOR THE PROPER PROCEDURE.

PARTS INFORMATION:

PART NUMBER DESCRIPTION 24213271 PISTON-KIT

PARTS ARE CURRENTLY AVAILABLE AT GMSPO.

WARRANTY INFORMATION:

FOR VEHICLES REPAIRED UNDER WARRANTY, USE:

LABOR OPERATION LABOR OPERATION NUMBER DESCRIPTION TIME --------------- ----------- --------------- K7572 FORWARD/COAST - R AND R REPLACE USE PUBLISHED LABOR OPERATION TIME

FIGURES: 3 ATTACHMENTS: 0

FIGURE 1 - HYDRA-MATIC 4T80-E TRANSAXLE IDENTIFICATION INFORMATION FIGURE 2 - FORWARD AND COAST CLUTCH COMPONENT IDENTIFICATION FIGURE 3 - PREVIOUS AND REVISED FORWARD CLUTCH PISTON ASSEMBLY

Object Number: 336576 Size: FS

Object Number: 336578 Size: FS

Object Number: 336580 Size: MF

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.