I still haven't had a chance to look yet but for now I think I'm going to pass, a nice brass knurly knob is sounding good. Thanks very much for the offer, at least now you know where it is.
Johnwa - the MIL spec manual seems to be the only manual I have that shows the retainer as well, if it creeps again I'll make the retainer for it. Did you built the preload adjuster tool on page 25? My spindle seems a bit stiff (not unreasonable) but that may be just from sitting for a few years. I'll get a few hours of run time before I start messing with things.
Super user you just know it's going to creep again, make the darn retainer. Ya just do it.