A/T - Speed Sensor Bore Plug Missing/Leaking

Group Ref.: Transmission
Bulletin No.: 377145
Date: December, 1993

SUBJECT:
MISSING OR FLUID LEAKING - OUTPUT SPEED SENSOR BORE PLUG (INSTALL NEW PLUG)

MODELS:
1994 CHEVROLET AND GMC K-TRUCKS WITH 4WD ONLY

TRANSMISSION APPLICATIONS:
1994 HYDRA-MATIC 4L80E/4L80EHD

TRANSMISSION MODELS:
ACP, DLP, BJP, LFP

CONDITION:

The Output Speed Sensor Bore Plug may fall out or fluid may leak past the plug.

On all 1994 4L80-E 4WD models, the T.O.S.S. has been removed and a plated steel bore plug is installed. The output speed sensor reluctor ring is also eliminated on these models. The output speed/vehicle speed is obtained from the output speed sensor in the transfer case.





TRANSMISSION IDENTIFICATION INFORMATION

SERVICE INFORMATION:

Use the following procedure for replacement of the [1][2]speed sensor bore plug.

1. Raise the vehicle and support with safety stands.

2. Disconnect the transmission pass through wiring harness.

3. Use a chisel to cut a hole in the bore plug. DO NOT INSERT THE CHISEL INTO THE TRANSMISSION. INTERNAL COMPONENT DAMAGE COULD OCCUR.

4. Insert a pry bar or screwdriver into the hole in the bore plug and pry the bore plug out.

5. Install the new [1][2]speed sensor bore plug into the transmission case by inserting a socket in the center of the bore plug and tapping it in with a hammer until the lip of the bore plug is snug against case. THE USE OF A SEALER IS NOT RECOMMENDED ON THE BORE PLUG. INTERNAL COMPONENT DAMAGE COULD OCCUR IF SEALER ENTERED THE TRANSMISSION.

6. Connect the transmission pass through connector.

7. Lower the vehicle.





WARRANTY INFORMATION:

For vehicles repaired under warranty, use:

SERVICE PARTS INFORMATION:

PART NUMBER DESCRIPTION

8684222 Plug, [1][2]Speed Sensor Bore

Parts are currently available through GMSPO.