FLUID LEAK FROM HOUSING VENT INSTALL REMOTE VENT

TRANSMISSION APPLICATIONS: SUBJECT: ------------------------- ------- 1988 HM-117 MANUAL TRANSMISSION FLUID LEAK OUT OF THE VENT (RPO M20)

TRANSMISSION MODELS: VEHICLE APPLICATIONS: ------------------- -------------------- GGD, GGG, YAY AND YBY 1988 C AND K TRUCKS

Bulletin Covers:

A 1988 C/K Truck with a HM-117 manual transmission may develop a fluid leak out the vent.

NOTE: Figure 1 Transmission Identification information.

DATE OF PRODUCTION CHANGE:

Start of Production for the 1988 Model Year.

SERVICE ACTION:

The addition of a remote vent will prevent fluid from leaking out of the cover vent. To repair, perform the following:

1) Remove transmission (also transfer case if applicable).

2) Remove existing vent.

3) Install a vent sleeve and pipe assembly in the vent tube hole (Figure 2).

Note: Install with dull wide blade screwdriver

End of the fitting should point towards clutch housing.

4) Attach 660mm (2'6") of 8.00mm (5/16") I.D. hose to the pipe assembly and secure it with a worm type clamp.

5) Reinstall transmission (also transfer case if applicable).

6) Install a NEW vent assembly in the end of the hose.

7) Secure the hose to the large wire harness underhood on the passenger side of the engine cowl with a plastic tie wrap (Figure 3).

SERVICE PARTS INFORMATION:

Part Number Part Name ----------- --------- 08652580 Vent Sleeve and Pipe Assembly 09439104 8.00mm (5/16") I.D. Hose X 660mm (2'6") 25518880 Clamp, worm type, 6.5mm - 16.0mm (1/4" - 5/8") 08640496 Vent Assembly 03816659 Plastic Tie Wrap

SERVICE MANUAL REFERENCE:

Refer to transmission replacement in the on-vehicle service section of the appropriate service manual for procedures.

SERVICE NOTES:

1) Model designation YAY is the updated version of GGD and YBY is the updated version of GGG.

2) The 117mm will now be referred to as the HM-117.

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.