I've been trying to get my father's 1970 model 4400 industrial tractor/three point hitch back up and in running order. It's been sitting outside for about 4 years without being used. After problems with injection pump metering valve being stuck, I now have the tractor running fine. Now with the present problem(s.(1) It's been about thirty years since I had anything to do with the tractor and I've forgot where to check the diff/hyd oil. I think I remember there's a case plug somewhere but for the life of me I can't remember where and which one. (2) Also, I'd like to change the hyd oil and filter (if it even has a filter) and would like to know proceedures and cautions to watch out for. (3) As I was attempting to crank and start the engine, the very first time I tried, the three point began to raise upon initial cranking, even with a heavy box blade attached. I thought, "this is a good thang!" Well it does raise with each turn of the engine. However, once it reaches the full up position it won't lower when the control is moved to the lower position. I've tried it with draft lever in both positions and with speed valve both in and out positions. I'm using the tractor to move round hay bales with the loader and since the three point travels with the blade in the up position I thought with time some miricle might happen and it would cure itself. Once, after hitting a rather rough bump, the blade did lower to ground level then slowly returned back to full up position. When parked, it takes several days to leak back down but when starting again it raises fully up no matter which position the control is in. I've searched previous posts here and have gleaned that it's probably a spring return spool valve stuck from rust or something. And, that I'll have to take the cover off to access it. I don't have any manuels, however, I do have a lot of determination and a fair ammount of mechanical knowledge....just not about tractor rear end hydraulics. If possible, with the rather wordy description I've given, I would appreciate some detail on what steps to take, gaskets/seals needed to do the job, do's and don'ts and, how to clean up the spool valve and valve cylinder body, etc. Oh yeah, there is a aux valve mounted on top of the cover that is hooked to the ripper teeth which is working fine, with the exception that a seal is leaking in the remote cylinder (Different problem, Different day). Does this valve need to be removed or can it stay put when I remove the cover? I realize I may be asking for a lot of time and trouble but I will be greatly appreciative for any help and advice. Thank You,
Jerry
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