Oil Bypass

[jimmy_stikx]

Good to know.

I feel like I have a lot to learn with these trucks. I have an overwhelming urge to integrate the things I know from v8 performance into the M's architecture and have never seen a bellhousing with an open port on the underside before.

[MSeriesRebuild]

The fact here is that most rear main oil seals leak a little, until they are upgraded with the better seals of today which will stop the dripping. This open port allows the oil to escape from the housing if a leak is present. Closure of this port traps the oil in the flywheel housing where it will eventually contaminate the clutch disc lining, causing slippage problems. The only time the port was intended to be plugged is during fording operations, to keep water out of the housing. All other times, the plug is to be stored in the glove box per military manuals.

[topellis]

Charles has it right on. No plug is installed there unless you are actually doing fording. In the M151 they told us to remove as soon as we were done fording as it was not good to leave the plug in. Not sure why. . Just did as the mechs said. The plug was always stored. And painted on the dash to install when fording.

Mark