4 SP OR 5SP MAN. TRANSMISSION DIAGNOSIS AND EXCHANGE

MODEL AND YEAR: 1988 C/K TRUCKS WITH MANU 4 SPEED (MCO OR 5 SPEED (MG5) TRANSMISSIONS

Until further notice any MG290 manual 4 speed or 5 speed transmission needing repair is to be reported to Chevrolet Technical Assistance Network for exchange. Dealership repair replacement may be made to the clutch or clutch release bearing.

DIAGNOSIS

Insure correct oil level. Insure that the clutch is working properly. Insure that all engine and transmission mounts are tight.

TRANSMISSION REMOVAL

Refer to the Chevrolet Service Manual ST-375-88 (1988 C/K truck)

NOTICE:

After removing the shift tower (exchange units are complete less shift tower assembly) cover the shift tower opening to prevent dirt from getting into the transmission during removal.

After installation of the new transmission use P/N 1052942 Loctite (gasket maker) in place of the shift tower gasket until parts are available.

Do not force the shift tower onto the transmission, this will cock the socket on the bottom of the shift tower and may damage the machined surface.

The shift control lever and jam nut on the 4-speed are left handed, while the 5-speed has right hand threads.

EXCHANGE PROCEDURES

1.Before calling T.A.N. to request an exchange, fillout the MCO/MG5 reporting form with all pertinent information. (Additional copies of the reporting form and oil leak chart should be reproduced locally.)

If the vehicle has an oil leak, determine where the leak is by using the oil leak identification chart. The noise and shifting charts can be filled in by using check marks. it will be necessary to record this information as it will be needed to fill out the form on the transmission being returned. (Blank form will be shipped with the new transmission.)

2.T.A.N. will provide an authorized "case request number". This number must be written on the clutch housing as well as the shipping container with a black marker pen.

3.T.A.N. will arrange to ship an exchange unit to the dealership.

4.The exchange unit will have an envelope attached to it which contains:

o Return Shipping Label o Administrative Procedures o MCO/MG5 Reporting Form (Reference Figures No. 2 and 3) o Return Shipping carrier Information o Identification Tag

5. Once the exchange unit is received, the removed transmission is to be returned to:

Hydra-Matic (Muncie) 1200 West Eighth Street Muncie IN 47302

6. The complaint unit must be returned within 8 to 10 days after the receipt of the exchange unit to avoid a chargeback.

PREPARATION FOR SHIPPING:

1. Drain the oil and replace the drain plug.

2. Remove plastic shipping plugs from the exchange unit and install them into the removed unit.

3. Fold the MCO/MG5 reporting form, staple it to the identification tag and secure the tag to the clutch housing of the removed transmission.

4. Write the T.A.N. "Case Request Number" on the clutch housing and shipping container with a black marker pen.

5. Repack the removed transmission into the exchange shipping container.

6. Place the shipping label on the shipping container.

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.