Any old bus experts out there?

We have an old ACF Brill tour bus (1947)here at the Honest Charley Garage that we are restoring for Corky Coker. The bus is pretty much finished, but I'm having trouble locating parts/or kit for the Spicer model 918 2 speed automatic transmission. This tranny was used in other applications besides bus's in the late forties, like some Mac trucks I believe?
I have hit a dead end with this thing! I know this isn't typical Hot Rod stuff, but it is pretty cool! any help would be greatly appreciated!

 

I work for a kenworth dealer, get on line its either eaton fuller .com or something close to that. spicer is part of eaton. they still support some way old truck trannys. no guarantee. but talk to the people that built it in the first place