I have been told that my differential/axle is either a Rockwell or a Dana 90? Any educated guesses,, as my coach and gillig manual, are 1800 miles away.. Can we say, "...because I have this type of chassis (Gillig), I probably have this type/brand of differential/axle..." And if it is a Rockwell, what model would it most likely be..?
Any of you Regency folks around 1990-1993 have any insight? Any pic's available for on some specific part or info plate that on either brand would make it apparent ?

Call Gillig with your vin and they can tell you exactly what was installed.

There should tags somewhere on the housing with information about it

Thanks T/J and Wrench, I have a call into them.. Also going to ask them
(from Gillig's POV/ Point of View) what bus chassis is under there also.. If they put that chassis under a bus, which one..Phantom Transit Coach, etc..might be helpful in searching for additional info and manuals. I do have their pricey chassis manual they sent me..but, of course its in Texas..

Gillig advises I have a Spicer/Dana J175 however, in the build sheet, it says F175 with a 4.10 ratio..
The brochure shows J175, it does not show F175..?

here's the brochure I located on line, also put in the "Ads, Documentation, Brochures/Schematics" section..
Spicer Single Speed Drive Axles

if interested, Gillig also sent me the build sheet for my chassis. .. It's in that thread also for reference..
Gillig Chassis build sheet...