Overdrive Solenoid

This procedure covers the replacement of the overdrive solenoid in the 48RE automatic transmission on a 2007 Ram 3500 with the 5.9L Cummins diesel engine.

Warnings

Tools required

Parts

• Overdrive solenoid (Governor pressure solenoid) × 1 — Use OEM Mopar specification for 48RE transmission
• Transmission pan gasket × 1 — Use OEM specification
• Transmission filter × 1 — Recommended replacement during service
• Valve body gasket × 1 — Use OEM specification
• Solenoid O-rings × 1 — Usually included with solenoid

Fluids

• ATF+4 — 6 qt

Preparation

1. Park vehicle on level surface and set parking brake firmly
2. Place wheel chocks behind rear wheels
3. Start engine and allow to reach operating temperature, then shift through all gear ranges 2-3 times to circulate fluid
4. Shut off engine and allow transmission to cool for at least 30 minutes
5. Raise front of vehicle and support securely on jack stands rated for vehicle weight
6. Remove skid plate if equipped to access transmission pan
7. Clean exterior of transmission pan and surrounding area to prevent contamination

Procedure

1. 1

   Drain transmission fluid
   Position drain pan under transmission pan. Loosen all transmission pan bolts approximately 2-3 turns but do not remove. Carefully loosen one corner of the pan to allow fluid to drain in a controlled manner. Tilt pan as needed to drain most fluid, then remove remaining bolts and lower pan. Expect 4-6 quarts to drain initially.
2. 2

   Remove transmission pan and filter
   Once pan is removed, set aside and allow remaining fluid to drain. Remove the transmission filter by pulling straight down - it is held by an O-ring seal. Inspect filter for metal debris or clutch material which may indicate larger transmission issues. Remove and discard old pan gasket material from both pan and transmission case using a scraper, being careful not to gouge sealing surfaces.
3. 3

   Access valve body
   Locate the valve body inside the transmission. You will see multiple solenoids attached to it. On the 48RE, the overdrive solenoid is a distinct component from the governor pressure solenoid — verify which solenoid you are targeting before proceeding. Take a photo or make note of all electrical connector positions and wire routing before disconnecting anything.
4. 4

   Disconnect electrical connectors
   Carefully disconnect the electrical connector from the overdrive solenoid. Press the locking tab and pull straight up. Note the orientation and routing of the wiring harness. If connector is difficult to remove, use a small flathead screwdriver to carefully release the lock tab.
5. 5

   Remove overdrive solenoid mounting bolts
   Remove the solenoid mounting bolts using the appropriate Torx or hex driver — verify the exact drive type and size against the actual fasteners before applying force. Keep bolts organized and note their positions as they may be different lengths. Support solenoid while removing final bolt to prevent it from falling.
6. 6

   Remove old solenoid
   Gently pull the overdrive solenoid straight out of the valve body. It may require slight twisting motion to break the O-ring seal. Inspect the solenoid bore in the valve body for debris, scoring, or damage. Note the condition and orientation of the old solenoid for comparison with new part.
7. 7

   Prepare and install new solenoid
   Compare new solenoid to old unit to verify correct replacement. Install new O-rings on new solenoid if not pre-installed. Lightly lubricate O-rings with clean ATF+4 fluid. Clean the solenoid bore with brake cleaner and compressed air if available. Insert new solenoid straight into valve body, ensuring proper alignment and that O-rings seat correctly without pinching.
8. 8

   Install solenoid mounting hardware
   Install solenoid mounting bolts finger-tight first to ensure proper alignment. Tighten bolts in a cross pattern to the manufacturer's published torque specification for the 48RE — do not estimate, as under- or over-torquing internal fasteners can cause damage or leaks. Reconnect electrical connector ensuring it clicks into place and lock tab engages.
9. 9

   Install new filter and gasket
   Install new transmission filter by pressing straight up into position until O-ring seats. Clean transmission pan thoroughly with brake cleaner and dry completely. Install new pan gasket on transmission case, ensuring alignment with all bolt holes. Some gaskets are adhesive-backed, others may require alignment pins or careful handling.
10. 10

    Reinstall transmission pan
    Carefully position transmission pan to gasket, ensuring gasket stays in place. Start all pan bolts by hand to prevent cross-threading. Tighten pan bolts progressively in a crisscross pattern around the perimeter to the manufacturer's published specification (approximately 12-13 ft-lbs / 150-165 in-lbs for the 48RE) - do not over-tighten as this can distort the pan and cause leaks.
11. 11

    Reinstall skid plate
    If skid plate was removed, reinstall it using original hardware. Ensure proper clearance and alignment before fully tightening fasteners.
12. 12

    Refill transmission fluid
    Lower vehicle to ground. Locate transmission dipstick tube and insert funnel. Add approximately 5 quarts of ATF+4 initially. Start engine and allow to idle in park. With engine running and parking brake set, shift through all gear positions, pausing 2-3 seconds in each. Return to park and check fluid level with engine running. Add fluid as needed to bring to proper level on dipstick (check in PARK with engine at idle and fluid at operating temperature).

Reassembly

1. Ensure all electrical connectors are fully seated and locked
2. Verify transmission pan bolts are tightened in proper sequence to prevent leaks
3. Double-check that transmission fluid is at proper level on dipstick with engine running at operating temperature
4. Install skid plate if it was removed for access

Verification

• Start engine and verify no transmission fluid leaks from pan or any disturbed connections
• Allow engine to reach normal operating temperature with transmission in park
• Test drive vehicle and verify smooth shifting through all gears including overdrive engagement
• Verify no transmission warning lights or diagnostic codes are present
• After test drive, recheck fluid level with engine running at operating temperature and top off if necessary
• Inspect under vehicle after test drive for any signs of fluid leakage
• Verify overdrive function by monitoring tachometer drop when transmission shifts into overdrive (typically around 45-50 mph under light throttle)

Related trouble codes on this vehicle

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