NEW OIL PUMP ROTOR THICKNESS

Model and Year: 1989 A, J, L CARS WITH THM 125C/HYDRA-MATIC 3T40 TRANSAXLES

TO: ALL CHEVROLET DEALERS

BULLETIN COVERS: (Figure 1) --------------- New Oil Pump Rotor thickness for all THM 125C/HYDRA-MATIC 3T40 transaxles.

DATE OF PRODUCTION CHANGE:

Oil Pump Rotors with the new thickness went into production March 16, 1989, (Julian Date 075), for all THM 125C/HYDRA-MATIC 3T40 transaxles.

SERVICE ACTION:

A one inch Vernier micrometer is required to measure rotor thickness. Measurement must be made on undamaged surface. (Refer to Figure 1)

Use the original rotor measurement to determine which rotor package to order, which includes both the rotor, slide and vanes.

SERVICE PARTS INFORMATION:

Whenever ordering New Oil pump rotors refer to the following chart and part numbers. Oil Pump Rotor Selection Chart ------------------------------ Part Number Rotor Thickness (mm) Rotor Thickness (inches) ----------- -------------------- ------------------------ 8665951 17.9120 - 17.9219 0.7052 - 0.7055 8665952 17.9220 - 17.9319 0.7056 - 0.7059 8665953 17.9320 - 17.9419 0.7060 - 0.7063 8665954 17.9420 - 17.9519 0.7064 - 0.7067 8665955 17.9520 - 17.9619 0.7068 - 0.7071

Parts are expected to be available on 9/1/89. Until then normal part orders will not be accepted by GMSPO. Only verifiable emergency VIP orders will be accepted. SPO will make every effort to obtain parts. All parts will be placed on 400 control to waive VIP surcharges. However, the part will be shipped premium transportation at dealer's expense. All other order types will be cancelled as incorrectly ordered while the 400 control is in place.

SERVICE MANUAL REFERENCE:

Refer to the Unit Repair Section of your Service Manual whenever replacement of the Oil Pump Assembly is necessary.

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.