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 459 (AUTOMATIC TRANSAXLE DIAGNOSIS, SERVICE & REPAIR - 4T65-E)REPAIR INSTRUCTIONSCONTROL VALVE BODY REPLACEMENTREMOVAL PROCEDURE

1999 GMC Forward Control 5.7 R, Automatic

Removal Procedure

1999 GMC Forward Control 5.7 R, AutomaticSECTION Removal Procedure

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

Remove the case side cover. Refer to CASE SIDE COVER REPLACEMENT .
Remove the oil pump. Refer to OIL PUMP REPLACEMENT .
Remove the valve body bolts (374-381, 384).

Fig 1: Removing Control Valve Body (1 Of 6)
Courtesy of GENERAL MOTORS CORP.
Remove the valve body (300) while keeping the spacer plate (370) with the transaxle.

Fig 2: Removing Control Valve Body (2 Of 6)
Courtesy of GENERAL MOTORS CORP.
Remove the ball check valves (372, 373) from the valve body.

Fig 3: Removing Control Valve Body (3 Of 6)
Courtesy of GENERAL MOTORS CORP.
Remove the spacer plate (370) and gasket.

Fig 4: Removing Control Valve Body (4 Of 6)
Courtesy of GENERAL MOTORS CORP.
Remove the ball check valves (372) from the case cover.

Fig 5: Removing Control Valve Body (5 Of 6)
Courtesy of GENERAL MOTORS CORP.
Inspect each check valve seat in the spacer plate (370) for excessive peening. 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. Refer to the Transmission/Transaxle/Transfer Case Unit Repair Manual.

Fig 6: Removing Control Valve Body (6 Of 6)
Courtesy of GENERAL MOTORS CORP.

RENDER: 1.0x

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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.