This TSB applies to 2003 and later Honda Pilot and 2006 and later Ridgeline vehicles.
SYMPTOM: There is a noise and a judder (shake/vibration) from the rear when turning.
PROBABLE CAUSE: The VTN-4 differential fluid is contaminated by clutch wear, condensation or both. This causes the VTM-4 clutches to make noise and to judder when turning.
NOTE: Worn VTM-4 fluid that has not been replaced at the recommended service intervals can cause the same condition.
The VTM-4 differential fluid must be changed.
Drain plug washer (18 mm, drain plug sealing washer) P/N 90471-PX4-000, HC 3300936
Drain plug washer (20 mm, filler plug sealing washer) P/N 94109-20000, H/C 0251728
VTM-4 differential fluid (five quarts required) P/N 08200-9003, H/C 6512651
Perform 10 figure-eight patterns with the steering wheel at full lock. Listen for a noise and feel for a judder. Accelerate at the start of each circle to make sure that the clutches engage and disengage. Do not use the VTM-4 LOCK button.
If you can hear a noise and/or feel a judder, go to Repair Procedure. If you cannot hear a noise or feel a judder continue with normal troubleshooting.
- With the engine off, raise the vehicle on a lift in a level position.
- Remove the differential filler plug and its sealing washer, Save the sealing washer.
- Remove the differential drain plug and washer to drain the VTM-4 fluid. Save the sealing washer. The drained fluid should look red. If it looks pink, this means that water has entered the VTM-4 differential through the vent tube breather in the rear subframe. This can happen when launching a boat or driving through water deep enough to cover the tires. If the fluid looks pink, replacing the fluid may not eliminate the noise/judder issue.
- Clean the drain plug and reinstall along with the sealing washer. Torque the plug to 35 ft.-lbs. (47 N-m).
- Fill the differential with VTM-4 fluid until the fluid level reaches the bottom of the filler hole. To avoid contamination, always fill from an unopened container. Always use a dedicated hand-operated fluid pump (P/N 07AAK-PGJA220 or equivalent. Never use a pump driven by compressed air.
- Reinstall the filler plug and sealing washer and torque the plug to 35 ft.-lbs. (47 N-m).
- Drive the vehicle in a figure-eight pattern with the steering wheel at full lock. Accelerate at the start of each circle. Complete at least 10 patterns.
- With the engine off, raise the vehicle on a lift. Remove the filler plug and its sealing washer, and discard the sealing washer.
- Remove the drain plug and sealing washer to drain the VTM-4 differential fluid. Discard the sealing washer.
- Clean the drain plug and reinstall with a new 18mm sealing washer. Torque the plug to 35 ft.-lbs.
- Fill the differential with fresh VTM-4 fluid until the level reaches the bottom of the filler hole.
- Reinstall the filler plug with a new 20 mm sealing washer and torque the plug to 35 ft.-lbs.
- Test drive the vehicle in a figure-eight pattern again to confirm that the noise and judder are gone. Accelerate at the start of each circle. You may need to perform up to 10 patterns to get rid of the noise and judder.
After first draining and refilling the differential, re-use both original sealing washers. After circulating the fresh fluid during your test drive, always use new sealing washers when refilling for the final time.