Replace the overdrive solenoid in the automatic transmission to restore proper shifting and overdrive function.

Warnings

Tools required

Parts

• Overdrive solenoid assembly × 1 — Use OEM specification
• Transmission pan gasket or RTV sealant × 1 — Use OEM specification
• Transmission drain plug crush washer × 1 — Use OEM specification
• O-ring for solenoid (if not included with solenoid) × 1 — Use OEM specification

Fluids

• Toyota WS ATF — 4.5 qt

Preparation

1. Park vehicle on level ground and engage parking brake
2. Allow transmission to cool to ambient temperature if recently driven
3. Raise and support vehicle securely on jack stands at all four corners
4. Remove plastic undertray/splash shields to access transmission pan
5. Disconnect negative battery terminal to prevent any electrical faults during solenoid replacement
6. Place drain pan under transmission drain plug

Procedure

1. 1

   Drain transmission fluid
   Remove the transmission drain plug using a 14mm socket. Allow fluid to drain completely into the drain pan. Inspect the fluid for metal particles or burnt smell indicating other transmission issues. Once drained, install a new crush washer on the drain plug and reinstall.
   Torque spec

   Drain Plug34 Nm (25 lb-ft)
2. 2

   Remove transmission pan
   Remove all transmission pan bolts in a criss-cross pattern using a 10mm socket. Start by loosening all bolts, then remove them completely working from the edges toward the center. Carefully lower the pan as residual fluid will drain. Clean the pan thoroughly and inspect the magnet for excessive metal debris.
   ⚠Approximately 1-2 quarts of fluid will drain when pan is removed. Keep drain pan positioned appropriately.
   Torque spec

   Pan Bolts16 Nm (12 lb-ft)
3. 3

   Locate overdrive solenoid
   With the transmission pan removed, locate the overdrive solenoid on the valve body. It is typically positioned on the driver's side of the valve body assembly and will have an electrical connector attached. Reference the service manual diagram if needed for exact location on the U760E/U661E transmission.
4. 4

   Disconnect solenoid electrical connector
   Carefully disconnect the electrical connector from the overdrive solenoid. Press the locking tab and pull straight out to avoid bending pins. Inspect connector terminals for corrosion or damage.
5. 5

   Remove overdrive solenoid mounting bolts
   Remove the solenoid mounting bolts using a 10mm socket. Keep track of bolt locations as they may be different lengths. Carefully wiggle the solenoid to break it free from the valve body.
   ⚠Do not pry against the valve body as this can cause damage to the aluminum casting.
   Torque spec

   Sensor Bolts11 Nm (8 lb-ft)
6. 6

   Remove old solenoid and O-ring
   Pull the solenoid straight out from the valve body. Remove and discard the old O-ring from the solenoid bore. Clean the mounting surface on the valve body with a clean shop rag, ensuring no debris falls into the transmission.
7. 7

   Install new solenoid
   Lubricate the new O-ring with clean ATF and install it on the new solenoid. Insert the solenoid into the valve body bore, ensuring it seats completely and the bolt holes align. Install the mounting bolts finger-tight initially.
8. 8

   Torque solenoid mounting bolts
   Torque the solenoid mounting bolts to specification using a torque wrench. Tighten in a criss-cross pattern if multiple bolts are present.
   Torque spec

   Sensor Bolts11 Nm (8 lb-ft)
9. 9

   Reconnect electrical connector
   Reconnect the electrical connector to the new solenoid, ensuring it clicks into place and the locking tab engages fully. Verify the connection is secure by gently pulling on the connector.
10. 10

    Clean and prepare transmission pan
    Thoroughly clean the transmission pan and mating surface on the transmission case. Remove all old gasket material or RTV. Clean the magnet in the pan. Apply new gasket or RTV sealant according to manufacturer specifications.
    ℹ️If using RTV, allow proper cure time before filling with fluid. Check RTV specifications for cure requirements.
11. 11

    Reinstall transmission pan
    Position the transmission pan with new gasket onto the transmission case. Install all pan bolts finger-tight. Tighten bolts in a criss-cross pattern to proper torque specification, working from the center outward.
    Torque spec

    Pan Bolts16 Nm (12 lb-ft)
12. 12

    Refill transmission fluid
    Lower the vehicle temporarily. Remove the transmission fill plug on the side of the transmission case. Using a fluid pump and funnel, add approximately 4.5 quarts of Toyota WS ATF through the fill hole. Reinstall fill plug to specification.
    ⚠Do not overfill. Overfilling can cause foaming and transmission damage.
    Torque spec

    Fill Plug34 Nm (25 lb-ft)
13. 13

    Check fluid level and test
    Reconnect battery. Start the engine and cycle through all gear positions, pausing 2-3 seconds in each. With engine running and transmission at operating temperature (160-180°F), check fluid level through fill plug hole. Fluid should be level with bottom of fill hole. Add or drain as necessary.

Reassembly

1. Reinstall all undertray panels and splash shields removed during preparation
2. Lower vehicle from jack stands
3. Verify all tools and parts have been removed from under vehicle
4. Dispose of old transmission fluid according to local regulations

Verification

• Start engine and verify no transmission fluid leaks from pan or drain plug
• Test drive vehicle through all gears including overdrive to confirm proper shifting
• Verify overdrive engages smoothly at highway speeds (typically 45+ mph)
• Check transmission fluid level again after test drive with transmission at operating temperature
• Use OBD-II scanner to verify no transmission-related diagnostic trouble codes are present
• Monitor transmission operation over the next few days to ensure proper function

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