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.

SYS.OK|MANUAL.DB● LIVE

HOMESERVICE MANUALSGMC1999FORWARD CONTROL 5.7 R, AUTOMATICREPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 588 (AUTOMATIC TRANSAXLE - 4T65-E (INTRODUCTION, SERVICE & REPLACEMENT))REPAIR INSTRUCTIONSTRANSMISSION FLUID PRESSURE (TFP) MANUAL VALVE POSITION SWITCH 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 2004 Pontiac Aztek and 2004 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 .
Disconnect the transaxle wiring harness.

Fig 1: View Of TFP Manual Valve Position Switch

Courtesy of GENERAL MOTORS CORP.

Remove the control valve body bolts (375, 379 and 381) that mount the fluid pressure manual valve position switch to the control valve body (300).
Carefully remove the fluid pressure manual valve position switch. Handle the switch carefully, the fluid pressure manual valve position switch is very delicate.

Fig 2: Inspecting Fluid Pressure Manual Valve Position Switch

Courtesy of GENERAL MOTORS CORP.

Inspect the fluid pressure manual valve position switch (395) for the following conditions:
- Damaged electrical connector terminals
- Damaged seals
- Damaged switch membranes
- Debris on the switch membranes

RENDER: 1.0x

NO RELATED

Recommended Tools & Savings

Use the Manual With the Right Hardware

Pair factory procedures with proven DIY tools so the instructions are easier to execute.

Affiliate disclosure: We may earn a commission at no extra cost to you.

Shop Manual-Ready Tools Free Quote Check Quote Shield Pro

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.