TM-9-2320-272-24-1

TRUCK, 5-TON, 6X6, M939, M939A1, AND M939A2 SERIES TRUCKS (DIESEL)

TECHNICAL MANUAL; UNIT, DIRECT SUPPORT, AND GENERAL SUPPORT MAINTENANCE MANUAL; VOLUME 1 OF 4

JUNE 1998

TM-9-2320-272-24-1 - Page 620 of 1015

3-89. TACHOMETER

TM 9-2320-272-24-1

THIS TASK COVERS:

a. Removal

b. Installation

INITIAL SETUP:

APPLICABLE MODELS

M939/A1

TOOLS

REFERENCES (TM)

TM 9-2320-272-10

TM 9-2320-27224P

General mechanic’s tool kit (Appendix E, Item 1)

EQUIPMENT CONDITION

MATERIALS/PARTS

Rubber grommet (Appendix D, Item 565)

Parking brake set (TM 9-2320-272-10).

Left splash shield removed (TM 9-2320-272-10).

1.

Disconnect tachometer driveshaft (5) from tachometer pulse sender unit (12).

2.

Remove screw (1), washer (2), and loop clamp (3) from intake manifold (11).

3.

Remove rubber grommet (4) from firewall (6). Discard grommet (4).

4.

Remove eight screws (9) from instrument cluster (8).

5.

Pull instrument cluster (8) away from instrument panel (10).

6.

Disconnect tachometer driveshaft (5) from tachometer (7) on instrument cluster (8).

7.

Remove tachometer driveshaft (5) from engine side of firewall (6). Replace if bent or cracked.

1.

Push tachometer driveshaft (5) through hole in firewall (6) to tachometer (7).

2.

Install tachometer driveshaft (5) on tachometer (7).

3.

Install instrument cluster (8) on instrument panel (10) with eight screws (9).

4.

Slide new rubber grommet (4) over disconnected end of driveshaft (5) and install in firewall (6).

5.

Install driveshaft (5) on tachometer pulse sender unit (12).

6.

Position loop clamp (3) over driveshaft (5) and install on intake manifold (11) with washer (2) and

screw (1).

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