Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
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HOMESERVICE MANUALSCHEVROLET1988STEP VAN P20, 7.4 W, AUTOMATIC, 475/M40REPAIR AND DIAGNOSISTRANSMISSIONAUTOMATIC TRANSOVERHAUL - THM 400TRANSMISSION DISASSEMBLYREAR UNIT END PLAY CHECK
1988 Chevrolet Step Van P20, 7.4 W, Automatic, 475/M40
Rear Unit End Play Check
1988 Chevrolet Step Van P20, 7.4 W, Automatic, 475/M40SECTION Rear Unit End Play Check
- Transmission must be out of vehicle and extension housing must be removed. Install Speedometer Puller Bolt (J-21797) in an extension housing bolt hole. Install dial indicator.
- Zero dial indicator, move output shaft in and out, and note end play. See Fig 1. End play should be .007-.019" (.18-.48 mm). If not within specification, change thrust washer.
- Thrust washer controlling rear unit end play has 3 tabs. It is located between output shaft thrust washer and rear face of transmission case. Notches and/or numerals on tabs of washer identify thickness. See REAR UNIT THRUST WASHERS .
REAR UNIT THRUST WASHERS
| Washer Thickness | I.D. Notches | I.D. Numeral |
|---|---|---|
| .074-.078" | None | 1 |
| .082-.086" | Side 1 Tab | 2 |
| .090-.094" | Side 2 Tabs | 3 |
| .098-.102" | End 1 Tab | 4 |
| .106-.110" | End 2 Tabs | 5 |
| .114-.118" | End 3 Tabs | 6 |
RENDER: 1.0x
NO RELATED
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.