I May have one on the shelf - but needs to be put back together as a rebuild
unless ya wanna buy a completely rebuilt one that's been re-geared with the tere low gear set. 3.15 low range - compared to stock 2.too low - low range. Aint gonna be cheap though. I got it for my 72 though. But it's stuck on financial hold for now.
Or - there's always the one currently mounted in my barrel rolld 74 Scout - lol
edit**
or - there's the option of rebuilding your current d20 with the tera low gear set. Which I also have a complete kit still in the box - locked up in my spare locker bin in my man cave. Or rebuild your d20 with the stock gears and new bearings and seals & springs