DELAYED 1-2 SHIFT AT FULL- THROTTLE 86 F-BODY W/700R4

1986 FIREBIRD MODELS EQIUPPED WITH THM 700-R4 (MD8) AND 5.0L MPFI ENGINES

BULLETIN COVERS:

Service parts to correct a late 1-2 shift at full throttle on 1986 Firebird models equipped with 5.OL MPFI engines. These parts lower the full throttle 1-2 shift point to 4800 rpm.

DATE OF PRODUCTION CHANGE: (Figure 1) ------------------------- Beginning June 19, 1986 (Julian date 170) all 1986 YZM and YWM model THM 700-R4 transmissions were produced with these new parts. (See Service Parts Information)

SERVICE ACTION: (Figure 2) -------------- The Service Packages listed in Service Parts Information can be used on any 1986 YZM or YWM model THM 700-R4 transmission that exhibits a late 1-2 shift at full throttle condition.

SERVICE PARTS INFORMATION:

Service Package No. Contents Model Affected ----------- -------- -------------- 8648954 Instruction Sheet 6YWM Valve - Low Range Upshift (353) Valve - Low Range Downshift (321) Sleeve - Low Range Control (320)

8648955 Instruction Sheet 6YZM Valve - 2-3 Throttle (315) Sleeve - 2-3 Throttle Valve (313) Valve - Low Range Downshift (321) Valve - Low Range Upshift (353) Sleeve - Low Range Control (320)

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.