'91 1Ton and diesel ?....

[kevinr1970]

Looking at a '91 Crewcab diesel 2wd (dually) for a pretty good price locally. Am told it was a navy base truck and as such its never even been licensed. It has 65,000 original miles but is about as basic as can be. No A/C, cruise, carpet, etc. It does have a fith-wheel hitch in the bed.
I noticed that it had an overdrive dash indicator and was curious as I didn't think the 1Tons came with OD until a few years later. When I looked underneath the truck, the tranny pan looked like it was 1-1/2 feet long by about 1 foot wide? Is it possible that this is a newer style tranny like a 480LE or something like that?
Also, in another thread I saw that in the governmet (military) diesels they spec'ed them with higher fuel flow or something like that so they performed a lot better? Would something like this qualify?
As a 1Ton dually wouldn't this truck be geared pretty high (or low, or whatever?), like in the 3.93-4.11 range?
BTW, this is the "old" body style like 81-87.
Any comments are appreciated.