Looks to like very few OMC things had service manuals. For your machine (and mine) there is just the PM and OM. Some machines including yours had a hydraulic service manual. Stuff like the axle seals is included in the operators manual, or at least is in my 310 which looks like it could be similar vintage to yours. The 440 manuals are listed in all the usual places like ebay. Check with a mustang dealer, I just got genuine NOS factory manuals for mine for $15 each. Looking at the seal section in mine I dont see anything in the procedure that does not seem logical or different from what I have read about most of the older bobcats. If yours is the same as mine it does not look too bad. Mine the floor comes out with a million bolts then you are in the tank. It does note that it make take a press to get the shaft started out of the bearing. Its not clear if the shaft will slide out of the machine and then you have to press the bearings off or if you have to press it out of the machine.