G 2500 3/4 Ton Van V6-262 4.3L VIN Z (1992)
Transmission Speed Sensor: Customer Interest
A/T - No Upshift/Stuck in 1ST/No Codes/Exterior Leaks
BULLETIN NUMBER: 93-7A-58
SECTION: 7A
NUMBER: 10
CORPORATE REFERENCE NUMBER: 377118
DATE: April 1993
SUBJECT:
NO UPSHIFT/STUCK IN FIRST/NO CODES/EXTERIOR LEAKS (REPLACE SPEED SENSOR)
MODELS:
1991-93 C/K, R/V, P, AND G VEHICLES WITH 4L8O-E/4L80-EHD TRANSMISSIONS
CONDITION
Some 1991-93 C/K, R/V, P, and G Vehicles With 4L80-E/4L80-EHD transmissions may experience a no upshift, stuck in first with no Diagnostic
Trouble Codes (DTC) stored.
CAUSE
Input/output speed sensor malfunction, or leaking (wicking) fluid through the speed sensor connector (internal and/or external). If the input speed sensor
is not functioning correctly, the output speed sensor is not used for reference by the PCM/TCM and an upshift cannot occur.
CORRECTION
Diagnose per the input speed sensor circuit check as outlined in Section 7A of the appropriate service manual. Replace the speed sensor if necessary.
DATE OF PRODUCTION: (Figure 1)
Starting January 15, 1993 (Julian Date 015) all 1993 C/K, R/V, P, and G Vehicles With 4L80-E/4L80-EHD transmissions will have the new speed
sensor assemblies.
SERVICE PARTS INFORMATION
Part #
Description
8685042
Speed Sensor Assembly
WARRANTY INFORMATION
For vehicles repaired under warranty, use:
Labor Codes:
Replace input sensor K6311 or output sensor K6312.
Parts are expected to be available on March 22, 1993.
