M/T - HM-290 Diagnostic Information: Overview

88chevy24

GMC NUMBER: 88-T-118


GROUP: 7B - Manual Transmission

DATE: May, 1988

CORPORATE
NUMBER: 877209
SUBJECT: HM-290 MANUAL TRANSMISSION DIAGNOSIS INFORMATION

MODEL: 1988 C/K TRUCKS EQUIPPED WITH HM-290 4 OR 5 SPEED MANUAL TRANSMISSIONS (OPTION MCO, MG5)

FIGURE 1 - HM-290 TRANSMISSION IDENTIFICATION INFORMATION RPO MCO/MG5:

BULLETIN COVERS: (Figure No.1)

Diagnosis information on 1988 C/K truck applications equipped with a HM-290 4 or 5-speed manual transmission. This information was gained from the now expired exchange program disassembly analysis of returned transmissions. Before repairs are attempted, refer to the following diagnostic chart as a guide.
SERVICE ACTION:

Preliminary Diagnosis Procedure
- Insure correct fluid level and proper type.
- Insure that the clutch is working properly (spin-down time and lost motion) (Reference 1988 C/K Manual X- 8731, Section 7B page 1 and 7C page 1).
- Insure that all engine and transmission mounts are tight.