I have a 1974 1855 Diesel. Great old machine. You have several points of fluid. 1. the engine dipstick is were you would expect on the left side of the engine block. 15w/40. 2. Same side of engine and just past the engine dipstick is the Over/Under Hydraulic Shif. Little cap on it with a dipstick attached. Takes AF2 Auto Trans fluid typ A. 3. Hydraulic Unit on back of tractor. Has a large cap with dipstick. On right hand side of tractor if standing behind unit. Takes type 55 Hyd Oil. 4. Transmission and Final Drive. A little cap/filler plug under and behind the seat at the top of the unit. Takes 80/90 Gear Oil. Lots of it. 44 qrts of it. Maintain fluid level at bottom of the TOP test plug hole located lower and next to the PTO shaft.
As to your cold moving 1755, my 1855 when started sometimes does not want to steer or the 3 point hitch move up or down. My levels are all up and unit seems that is is warmed up. I found ( and this makes no sense to me) that if I shut off the tractor. Let it set for just a few seconds and start it back up, the steering works perfect and the 3point hitch moves just perfect. I have never figured it out. I used to think it was due to cold, but every time it happens, I just kill the engine for a second or two and I mean just a couple of seconds, start it back up and I have power steering and good Hydro"s all around.