New to military vehicles so all help is greatly appreciated. Bought a 923, automatic, one owner before myself, older gentleman that just drove it in parades. Had a rebuild by the military before he bought it. I use it for farm work. Showing low miles and hours if accurate. I have put about 500 miles on it. When I put it in gear, fwd or reverse, the entire truck jerks. Is this normal? I checked the tranny fluid, engine running and temp on 180, was showing over the full mark. Dipstick is stamped something like check while running. Fluid looks clean and like it should, kind of the same as motor oil. Thanks in advance.