Toyota-Lexus-Subaru-Honda Differential/Final Drive Service

Toyota doesn’t have any recommendations as to whether to ever replace the gear oils for the final drive Toyota doesn’t have any recommendations as to whether to ever replace the gear oils for the final drive except in the case of severe use, in which case they say to replace it every 30k.

Our belief is that the differential oil should be changed every 30,000 miles in order to avoid premature wear and costly repairs. The distributor o-ring seals between the distributor housing and the engine to prevent engine oil from leaking out. As with other rubber seals, the rubber tends to get hard with age and to loose its resiliency. It becomes compressed as this happens and is no longer able to seal against the oil leaking past it.

Since the distributor is at the top of the engine, everything below the distributor ends up getting wet with oil as well. As a result, after you repair the known leak (the distributor o-ring), and after cleaning every thing else below it that was wet, you often have come back and recheck it later to see if there are any further leaks.

The distributor’s inner oil seal is to prevent oil from traveling from the engine through the distributor along its center shaft. Usually this can be resealed when it leaks.

Some times the seal will have worn a groove into the shaft, in which case the entire distributor housing needs to be replaced. For many vehicles, the ignition coil is located in the distributor. When the inner seal leaks and it soaks a portion of the ignition coil which almost always results in the ignition coil body swelling and cracking wide open.