Mess/seal/Core plug in transfer/transmission gear change housing

So, here I am preparing my old gearbox (R380) to go back to Winchester Gears and am taking off the gear change housing...
The gearchange housing is full of crud, oil grease and water emusified into a tasty spread ...



Well, having taken it apart a bit more I find the problem ..
There is (was) a seal on the control arm/rod that moves the selector that is 'inside' the gearbox. Oil is getting up and past the seal, along the shaft and into the the housing cavities ...
To get to the seal you need to remove the gearchange 'socket' and the selector plate from the arm... a lot easier to type than do BTW ... then slide the arm back to expose the O ring.



As you can see it's a bit flat. FRC4951 - not expensive but you have to buy 10 (or single from eBay etc at 800% profit).
To get the O ring off you need to get the shaft out .... there is a core plug in the way ... #597586, not expensive but you have to buy 10 or single @ 800% profit.



Are these a case of 'knock it out and do the opposite to refit ?"

If std looking core plug, yes. Maybe Britannica Mike has a video of these/this as he's recently been stripping/rebuilding an R380.

He does, I watched one a while back. Think it was on his own trucks but could be wrong.

Yup, knocked it out and will refit with a smidge of RTV.