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 MANUALSGMC1999FORWARD CONTROL 5.7 R, AUTOMATICREPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 130 (AUTOMATIC TRANSAXLE SERVICING)REMOVAL & INSTALLATIONCONTROL VALVE BODYREMOVAL

1999 GMC Forward Control 5.7 R, Automatic

Control Valve Body: Removal

1999 GMC Forward Control 5.7 R, AutomaticSECTION Removal

WARNING: This page is about a different car, the 2003 Buick Regal and 2003 Buick Century. However, it is still accessible from the selected car via links, so may be relevant.

Remove the case side cover. See CASE SIDE COVER . Remove the oil pump. See OIL PUMP . Remove the valve body bolts (374-381 and 384). See Fig 1 .

CAUTION: Carefully remove the valve body or the ball check valves will fall out.

Remove the valve body (300) while keeping the spacer plate (370) with the transaxle. See Fig 2 . Remove the ball check valves (372 and 373) from the valve body. See Fig 3 .
Remove the spacer plate (370) and gasket. See Fig 4 . Remove the ball check valves (372) from the case cover. See Fig 5 . Inspect each check valve seat in the spacer plate (370) for excessive peening. See Fig 6 .
Place a ball check valve (372) on each seat and use a flashlight in order to look for visible light between the valve and the seat. Inspect all components removed from the transaxle. See appropriate OVERHAUL article.

Fig 1: Identifying Valve Body Bolts

Courtesy of GENERAL MOTORS CORP.

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.