1-2 WIDE OPEN THROTTLE (NEW SPACER PLATE)

TRANSMISSION APPLICATIONS: SUBJECT: ------------------------- -------- 1988 THM 700-R4 (MD8) 1-2 WIDE OPEN THROTTLE "END BUMP" AND/OR 3-2 HIGH SPEED "TIE-UP"

TRANSMISSION MODELS: VEHICLE APPLICATIONS: ------------------- -------------------- 8YTM 4.3L B-CAR

Bulletin Covers:

Service parts for a 1988 YTM model THM 700-R4 transmission, which may exhibit a 1-2 wide open throttle "end bump" and/or 3-2 high speed "tie-up". An "end bump" is a firmer feel at the end of the shift as compared to the feel at the start of the shift. A "tie-up" is a condition where two opposing clutches, or band and clutch, are attempting to apply at the same time. A new 1-2 Accumulator Spring and new Valve Body Spacer Plate were introduced to improve shift feel and timing.

DATE OF PRODUCTION CHANGE: (Figure 1) ------------------------- Beginning March 28, 1988 (Julian Date 088) all 1988 YTM model THM 700-R4 transmissions were produced with the new 1-2 accumulator spring and valve body spacer plate.

SERVICE ACTION: (Figure 2) -------------- The Service Package listed in "Service Parts Information" can be used on any 1988 YTM model THM 700-R4 transmission (built prior to Julian Date 088) that exhibits a 1-2 wide open throttle end bump and/or 3-2 high speed tie-up.

SERVICE PARTS INFORMATION:

Service Pkg. No. Contents ---------------- -------- 8649997 Instruction Sheet Spring, 1-2 Accumulator (59) Plate, Valve Body Spacer (56) Gasket, Spacer Plate To Case (88) Gasket, Spacer Plate To Valve Body (89) Gasket, Transmission Oil Pan (72)

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.