Remove/Install rear main seal NHC250 M809

[onegmjack]

That's been a job Brian.Sometimes you just have to keep taking it apart to you get to where you can repair the problem.

 

[simp5782]

Update: Talked to the guys down at Memphis Eq. and they said the bell housing needs to come off with the style I have to get to the rear cover/oil seal housing. They also said very rarely, if at all, does the bell housing need to dialed back in. My seal should be here this week, so, probably this Sat. we'll dig deeper into this bad boy. My big concern is not taking off the housing it's safely suspending/jacking the engine while the housing is off.

Will, the O-ring goes on the back end of the rear cover where it meets the bell housing. Why? I don't know. Don't see why you would need one there. That should be a dry location between the housing and the block. Are we keeping something in or something out? Nonetheless, I ordered a new o-ring anyway.

I find it funny the military would design this truck with the rear main seal in such a work intensive location. Pulling the tranny, clutch and flywheel is one thing, OK, but having to remove the starter, flywheel housing and rear cover is a-whole-nother animal. Oh, well, just my thoughts.

Will bump this.

The Oring is used for a wet clutch housing to seal it. Also for fording to prevent water on crank case intrusion

The NHC250 and BiG Cam 1s share this rear main seal unit. On the Big Cam 1 with the CAT 7155 it is used to prevent transmission fluid from mixing with engine oil and leaking out the lower half since there is no way to seal it on the bottom

Big cam III rear main shown.

@Artisan had to swap his rear main housing on his engine swap to his 916 so that he had the O ring setup