A/T - New Oil Pump Rotor Thickness

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Number: 89-230-7A

Section: 7A

Date: August 1989


Corporate Bulletin No.: 977135


Subject:
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:

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.