This procedure covers the removal and replacement of all shift solenoids in the U660E automatic transmission, requiring transmission pan removal and internal valve body access.

Warnings

Tools required

Parts

• Shift Solenoid SL1 (Line Pressure) × 1 — 35250-0W080 or equivalent
• Shift Solenoid SL2 (Accumulator) × 1 — 35250-0W081 or equivalent
• Shift Solenoid SL3 (Lock-up Clutch) × 1 — 35250-0W082 or equivalent
• Shift Solenoid SL4 (Secondary Pressure) × 1 — 35250-0W083 or equivalent
• Shift Solenoid SLT (Linear Throttle) × 1 — 35250-0W084 or equivalent
• Transmission oil pan gasket × 1 — 35168-0W020 or equivalent
• Valve body cover gasket × 1 — Use OEM specification
• Transmission drain plug crush washer × 1 — 90430-12031 or equivalent
• O-rings for solenoids × 5 — Usually included with solenoids

Fluids

• Toyota WS ATF — 10 qt

Preparation

1. Verify the vehicle has been diagnosed and specific solenoid fault codes have been retrieved (P0750-P0770 range typical)
2. Ensure engine and transmission are completely cool to the touch
3. Park vehicle on level ground and set parking brake
4. Disconnect negative battery cable and wait 3 minutes for airbag system discharge
5. Raise vehicle securely on jack stands with front end elevated approximately 18 inches
6. Remove engine splash shield and under-body panels to access transmission
7. Place drain pan under transmission oil pan
8. Clean exterior of transmission pan and surrounding area with brake cleaner to prevent contamination

Procedure

1. 1

   Drain transmission fluid
   Remove the transmission drain plug located at the bottom of the pan using a 10mm hex socket. Allow fluid to drain completely (approximately 4-5 quarts will drain initially). Once drained, reinstall drain plug with NEW crush washer.
   ⚠Initial fluid rush can be forceful. Position drain pan carefully to avoid spillage.
   Torque spec

   Transmission Drain Plug30 Nm (22 lb-ft)
2. 2

   Remove transmission oil pan
   Remove all transmission pan bolts in a criss-cross pattern, loosening each bolt gradually to prevent pan warping. There are approximately 18-20 bolts around the perimeter. Once bolts are removed, carefully lower the pan. Additional fluid (2-3 quarts) will drain when pan is removed. Remove and discard old pan gasket, cleaning all gasket material from pan and transmission case mating surfaces.
   Torque spec

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

   Remove transmission fluid filter
   Locate the transmission filter secured to the valve body with three 10mm bolts. Remove these bolts and carefully lower the filter. Inspect filter for metal debris or excessive clutch material. Discard old filter and O-ring seal. Clean the filter mounting surface on the valve body.
4. 4

   Remove valve body cover
   The valve body cover is secured by approximately 14-16 small bolts (8mm heads). Remove these cover screws in a criss-cross pattern, keeping them organized as some may be different lengths. Carefully lift the cover straight up to avoid damaging the gasket surface. Note the positions of any check balls or springs that may be visible.
   ⚠Some solenoids may be partially visible now. Do not allow any check balls to fall out during this step.
   Torque spec

   Cover Screws11 Nm (8 lb-ft)
5. 5

   Identify and document solenoid locations
   Take photos or make detailed notes of solenoid wiring harness routing and connector positions. The U660E has 5 shift solenoids: SL1 (line pressure control), SL2 (accumulator control), SL3 (lock-up clutch), SL4 (secondary pressure), and SLT (throttle position). They are mounted on the valve body with individual 10mm bolts. Note wire colors and connector orientations for each solenoid.
6. 6

   Disconnect solenoid electrical connectors
   Carefully disconnect the electrical connectors from each solenoid by pressing the release tabs and pulling straight up. The connectors are typically green, gray, or black colored. Mark each connector with tape if necessary to ensure correct reinstallation. Inspect connector pins for corrosion or damage.
7. 7

   Remove shift solenoids
   Remove the mounting bolt from each solenoid (typically 10mm head). Carefully pull each solenoid straight out from the valve body bore. Some resistance is normal due to O-ring seals. Inspect each solenoid bore for debris or damage. Remove and discard old O-rings from each solenoid location.
   ⚠Each solenoid contains a small spring and check ball. Keep solenoids upright to prevent loss of internal components if they will be inspected.
   Torque spec

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

   Clean valve body and inspect
   Using brake cleaner and lint-free rags, thoroughly clean all valve body passages, solenoid bores, and mounting surfaces. Inspect for scoring, cracks, or excessive wear. Check that all fluid passages are clear and free of debris. Blow out passages with compressed air if available (use low pressure, 30 PSI maximum).
9. 9

   Install new solenoids
   Lubricate new O-rings on each solenoid with clean Toyota WS ATF. Install each solenoid into its correct bore, ensuring proper orientation (reference your photos from step 5). Push solenoid fully into bore until seated. Install and hand-tighten mounting bolts, then torque to specification. Install solenoids in order: SL1, SL2, SL3, SL4, then SLT.
   ⚠Do not over-torque solenoid bolts as this can crack the valve body casting. Use a proper torque wrench.
   Torque spec

   Sensor Bolts11 Nm (8 lb-ft)
10. 10

    Reconnect solenoid electrical connectors
    Reconnect each electrical connector to its corresponding solenoid, ensuring proper orientation and full engagement. You should hear or feel a distinct click when properly seated. Verify wire harness routing matches original configuration and wires are not pinched or stressed.
11. 11

    Install valve body cover with new gasket
    Position new valve body cover gasket carefully, ensuring all bolt holes and passages align correctly. Place valve body cover over gasket. Install all cover screws hand-tight first, then torque in a criss-cross pattern from center outward to specification.
    Torque spec

    Cover Screws11 Nm (8 lb-ft)
12. 12

    Install new transmission filter
    Install new O-ring on filter (lubricate with ATF). Position new filter onto valve body, aligning bolt holes. Install three mounting bolts and torque to specification (typically same as sensor bolts if not specified otherwise).
    Torque spec

    Sensor Bolts11 Nm (8 lb-ft)
13. 13

    Install transmission pan with new gasket
    Clean transmission pan thoroughly. Position new gasket on pan (some gaskets have adhesive backing). Lift pan into position carefully to avoid displacing gasket. Start all pan bolts by hand. Tighten bolts in criss-cross pattern gradually, working from center outward, to final torque specification.
    ⚠Do not over-torque pan bolts as this will distort the pan and cause leaks. Multiple light passes are better than one heavy pass.
    Torque spec

    Pan Bolts16 Nm (12 lb-ft)
14. 14

    Refill transmission fluid
    Through the transmission dipstick tube, add approximately 4 quarts of Toyota WS ATF initially. Start engine and allow to idle in Park. With engine running and parking brake applied, shift through all gear positions (P-R-N-D-L-2-1), pausing 3 seconds in each. Return to Park. Check fluid level with engine running at operating temperature. Add fluid as needed to bring level to COLD range initially.
15. 15

    Clear diagnostic codes and perform relearn
    Reconnect negative battery cable. Using a scan tool, clear all transmission-related diagnostic trouble codes. Perform TCM relearn procedure: Start engine, allow to reach operating temperature (180°F+), drive vehicle through all gears in normal driving for 10-15 minutes. The transmission will relearn shift points and solenoid calibration during this drive cycle.

Reassembly

1. Reinstall all under-body panels and splash shields removed during preparation
2. Verify all drain plugs and bolts are properly torqued and no leaks are present
3. After initial test drive, recheck transmission fluid level with engine at operating temperature in Park
4. Final fluid level should be between HOT range marks on dipstick
5. Monitor for any new warning lights or transmission fault codes

Verification

• Start engine and verify no transmission fluid leaks around pan, drain plug, or solenoid areas
• With engine at idle in Park, verify smooth engagement when shifting into Reverse and Drive
• Test drive vehicle and verify all gear changes occur smoothly without harsh shifts, flaring, or slipping
• Verify transmission does not stay in fail-safe mode (typically 3rd gear only)
• Using scan tool, verify all solenoid control values are within normal range and responding to commands
• Re-scan for diagnostic codes after test drive to confirm no new faults are present
• Check final fluid level with transmission at full operating temperature (190-200°F) and add fluid if necessary to reach proper level

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