M/T - Fluid Leak Out the Vent
87chevy13GMC NUMBER: 88-T-33
GROUP: 7B - Manual Transmission
DATE: August, 1987
CORPORATE
NUMBER: 877202
SUBJECT: FLUID LEAK OUT THE VENT
MODELS: 1988 C/K TRUCKS WITH HM-117 MANUAL TRANSMISSION (RPO M20)
FIGURE 1 - HM-117 TRANSMISSION IDENTIFICATION INFORMATION RPO M20:
A 1988 C/K truck with a HM-117 manual transmission may develop a fluid leak out the vent.
NOTE: Figure No. 1 - Transmission Identification Information.
SERVICE ACTION:
The addition of a remote vent will prevent fluid from leaking out the cover vent. To repair, perform the following:
1. Remove transmission (also transfer case if applicable).
^ If the model code on the I.D. tag is GGD or GGG refer to GMC campaign 88-C-03 or Chevrolet campaign 88-C-02.
NOTE: PERFORMING THE CAMPAIGN WILL NOT CORRECT THE FLUID LEAK OUT THE VENT. The remote vent MUST be added.
2. Remove existing vent.
FIGURE 2 - INSTALLING VENT SLEEVE AND PIPE ASSEMBLY:
3. Install a vent sleeve and pipe assembly in the vent tube hole (Figure No. 2).
-Position the end of the fitting toward clutch housing. -Install with dull wide blade screwdriver.
4. Attach 660 mm (2'6") of 8.00 mm (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.
FIGURE 3 - ENGINE COWL OF 1988 C/K TRUCK:
7.. Secure the hose to the large wire harness underhood on the passenger side of the engine cowl with a plastic tie wrap (Figure No. 3).
SERVICE PARTS INFORMATION
PART
NUMBER PART NAME
8652580 Vent Sleeve and Pipe Assembly
9439104 5/16" I.D. Hose X 660 mm (2'6")
8640496 Vent Assembly
3816659 Plastic Tie Wrap
25518880 Clamp, worm type, 1/4" - 5/8"
SERVICE MANUAL REFERENCE:
Refer to transmission replacement in the onvehicle 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 117 mm will now be referred to as the HM-117.