New Member/New Owner Needs Help

Just recently purchased a 1954 D2 5U. Blade leaks off slowly and drops down. Where should I be looking for the problem. I will be ordering books from Finney on Monday but would like some suggestions. Also can anyone give me types of fluids and quantities, also filter numbers to use in this dozer?
Thanks

Bob, Welcome. If your hydraulics are leaking down, chances are the cylinders will need new seals. Sometimes, you can tell which is required by it being hotter than the other, but when it's 100 degrees, they both probably feel hot. If you are rebuilding one, you might as well take care of them both, because chances are the other is soon to follow. If however, you are leaking fluid out of the system, a diagnosis of where the leak is originating from will change the course of action (obviously). You will need to tell us tractor and hydraulic unit serial numbers to get the proper answers. Also, is it a #44 or #41 hydraulic? Pics would be a help too.