Overdrive Solenoid

Replace the overdrive solenoid in the A-518 (46RH) automatic transmission, which controls fourth gear engagement. Requires transmission pan removal to access the valve body-mounted solenoid.

Warnings

Tools required

Parts

• Overdrive solenoid assembly × 1 — Mopar 4659872 or equivalent
• Transmission pan gasket × 1 — Use OEM specification
• ATF+3 automatic transmission fluid × 1 — Mopar ATF+3 Type 7176

Fluids

• ATF+3 automatic transmission fluid — 5 qt

Preparation

1. Park vehicle on level surface and engage parking brake.
2. Allow transmission to cool if recently operated (minimum 30 minutes).
3. Raise front of vehicle using floor jack at front crossmember and support on jack stands under frame rails behind front wheels.
4. Raise rear of vehicle to create level working position and support on jack stands under rear axle housing.
5. Verify vehicle is stable and all four jack stands are properly seated.
6. Position drain pan beneath transmission pan.

Procedure

1. 1

   Drain transmission fluid
   Locate the transmission pan at the bottom of the transmission case. The A-518 pan has no drain plug, so fluid will drain when pan bolts are loosened. Starting at the rear corner of the pan, loosen (but do not remove) all pan bolts approximately 4-5 turns using a 10mm socket. Gradually loosen the rear bolts further to allow the pan to tilt down at the rear and drain fluid into the drain pan. Control the tilt to avoid spilling. Once fluid flow slows, proceed to remove all bolts.
2. 2

   Remove transmission pan
   Remove all transmission pan bolts completely (there are 17 bolts around the perimeter). Carefully lower the pan, being aware that residual fluid will remain in the pan. Tilt and pour remaining fluid into drain pan. Set the pan aside on a clean work surface. Inspect the pan interior for metal debris or clutch material, which would indicate internal transmission wear requiring further diagnosis.
   ℹ️Presence of significant metal debris or friction material in the pan indicates transmission internal damage beyond solenoid replacement.
3. 3

   Remove transmission filter
   The transmission filter is held by 3 bolts to the valve body. Remove these three bolts using a 10mm socket and lower the filter assembly. Discard the old filter or set aside for reinstallation if only performing solenoid service. Note the filter neck seal orientation for reassembly.
4. 4

   Locate overdrive solenoid
   With the filter removed, identify the overdrive solenoid on the valve body. It is mounted on the driver's side of the valve body assembly, toward the rear section. The solenoid has a two-wire electrical connector and is held by a single bolt with a metal retaining bracket. The solenoid body is cylindrical with a screen filter on the inlet port.
   ⚠Do not touch or disturb other valve body components, check balls, or springs. Valve body disassembly is not required for solenoid replacement.
5. 5

   Disconnect solenoid electrical connector
   Locate the two-wire connector attached to the overdrive solenoid. The connector has a locking tab that must be depressed while pulling the connector straight off the solenoid terminals. Do not pull on the wires themselves. Note the connector orientation for reinstallation.
6. 6

   Remove overdrive solenoid
   Remove the single 10mm bolt securing the solenoid retaining bracket to the valve body. Remove the retaining bracket, then carefully pull the solenoid straight out of the valve body bore. The solenoid has an O-ring seal on the body that may stick in the bore. If stuck, gently twist while pulling to break the seal. Inspect the old solenoid screen filter for debris.
7. 7

   Inspect valve body bore and clean surfaces
   Inspect the valve body bore where the solenoid seats for debris, metal shavings, or scoring. Use a clean lint-free rag to wipe the bore clean. Check the solenoid retaining bracket for cracks. Clean the transmission filter mounting surface on the valve body using a plastic scraper to remove old gasket material. Do not use metal scrapers that could damage the aluminum valve body.
8. 8

   Install new overdrive solenoid
   Verify the new solenoid has an O-ring seal properly seated in the groove on the solenoid body. Lightly lubricate the O-ring with clean ATF. Align the solenoid with the valve body bore and push straight in until fully seated. The solenoid should sit flush with no gap between the solenoid flange and valve body surface. Install the retaining bracket and secure with the mounting bolt. Torque the bolt to specification.
   ⚠Solenoid must be fully seated before tightening retaining bracket or the valve body casting may crack.
9. 9

   Reconnect solenoid electrical connector
   Push the electrical connector onto the solenoid terminals until the locking tab clicks into place. Verify the connector is fully seated by gently pulling on the connector body (not the wires). The connector should not pull off.
10. 10

    Reinstall transmission filter
    Position the transmission filter with the neck seal properly oriented and align the filter bolt holes with the valve body. Install the three filter mounting bolts and torque to specification in a triangular pattern.
11. 11

    Clean and prepare pan for installation
    Thoroughly clean the transmission pan using solvent and a wire brush. Remove all old gasket material from the pan flange using a plastic gasket scraper. Clean the transmission case pan mounting surface, ensuring no old gasket material remains. Wipe both surfaces clean with a lint-free rag. Inspect the pan for cracks or damage, particularly around bolt holes.
12. 12

    Install pan with new gasket
    Position the new transmission pan gasket on the pan flange. The gasket should fit precisely over the pan with bolt holes aligned. Carefully lift the pan into position against the transmission case, holding the gasket in place. Start all 17 pan bolts by hand to hold the pan in position. Once all bolts are started, tighten them in a criss-cross pattern starting from the center and working outward. Torque all bolts to specification in the same criss-cross sequence.
    ⚠Over-tightening pan bolts will distort the pan and cause leaks. Use a torque wrench and follow the criss-cross tightening pattern.
    Torque spec

    Transmission Pan Bolts12 Nm (9 lb-ft)
13. 13

    Refill transmission fluid
    Lower vehicle from jack stands. Locate the transmission dipstick on the passenger side of the transmission case (red handle). Remove the dipstick and insert a long-neck funnel. Add 4 quarts of Mopar ATF+4 (backward-compatible replacement for the original Type 7176/ATF+ spec) fluid initially. Start the engine and allow it to idle. With the engine at idle and the transmission in Park, check the fluid level on the dipstick (do not shut off engine). The level should be in the cold range. Add additional fluid in 1-pint increments until the level reaches the upper cold mark. Total capacity after pan removal is approximately 5 quarts.
    ⚠Do not overfill transmission. Overfilling causes fluid aeration, foaming, and potential transmission damage.
14. 14

    Test overdrive operation
    With the engine at operating temperature and the vehicle on level ground, drive the vehicle through all gears. Accelerate normally and verify that the transmission shifts into overdrive (fourth gear) between 40-50 mph. The engine RPM should drop noticeably when overdrive engages. Test multiple times under varying throttle conditions. Check under the vehicle for any transmission pan leaks after test drive.

Reassembly

1. Ensure all pan bolts are torqued to specification in criss-cross pattern to prevent leaks.
2. Recheck transmission fluid level after test drive with engine at operating temperature, running in Park on level ground.
3. Final fluid level should be at the hot range mark on dipstick after transmission reaches operating temperature.
4. Minor seepage at the pan gasket during the first few heat cycles is normal and should seal as gasket compresses.

Verification

• Start engine and verify no Check Engine light illumination related to overdrive solenoid codes (typically P0760 or P0763).
• Test drive vehicle and confirm overdrive engagement occurs smoothly between 40-50 mph under normal acceleration.
• Verify transmission shifts down from overdrive when throttle is applied for passing or when manually shifted to third gear.
• Inspect transmission pan area for fluid leaks after test drive and first heat cycle.
• Confirm fluid level is in the hot range on dipstick with transmission at operating temperature, engine running, in Park.

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