Hello, I'm new here.. Iv'e been a member of Yesterdays Tractor, IBDozing which is now gone, for years now and just found this nice site. I have a Case 850C dozer for a few years now. Just recently I have been having troubles. I have replaced the charge pump, cleaned can filters under the seat and still seem to be having this problem. I can go out and get on the dozer fro about 45 minutes before it starts slowing down, not wanting to turn or go forward in high or low. It will go in reverse and operate. I have noticed that when it heats up I'm getting a good snail trail (oil trail) out the rear PTO shaft and that is when it seems to start slowing. I have replaced that seal twice and used speedy sleeves on it but cant seem to get it to stop. the shaft doesn't seem to be scared up and seems to be in good shape. I just cant get it to seal. My question is, could this be the cause of my problem? I was thinking that maybe when the trans oil heats up, it is passing through the leaking seal on the shaft instead of going to the forward clutches. Almost every 850 I see with a PTO shaft leaks. But my snail trail is pretty good. I keep the fluids topped off also. The Torque converter gauge never gets hot. I'm not a mechanic, but I know my way around this machine with the exception of the powershift operation and this has me confused. Could it be as simple as that leak at the PTO?
If it's pushing the seal out/ blowing by it, remove the two tubes that run down from the control housing two the end cap for the pto. Remove the six bolts and slide the housing off, be careful of the shims behind that little housing, once off you will see three seal rings on the shaft. The seal rings have a hook to make a complete circle on each grove in the shaft. They will wear and get thin over time and leak. Also on the end cap that you removed, look inside where the rings seal for wear and groves. I would check this first and then on to other areas if this did not help. If the oil is leaking out you will have a low pressure going to the clutch pack.
I've had it off several times and used a speedy sleeve over the shaft and new seal. It still leaks! I have another sleeve and will try it again. Is there a rebuild kit for that rear shaft area? Does what I describe sound like this might be the problem? I'll dig into it again next week.
I took the floorpans off today. Disconnected the brakes just in case they were hanging up. And now it won't go forward or reverse however the driveshaft is spinning at full rpm's.
You have a older machine, and that makes for its own issues. I don't think your oil leak is your issue for not moving. Sounds like your torque converter may be weak or your pressures may be low, as it is temperature related. You may have a bad relief, or pressure regulator. I have also had the hoses collapse on the older machines (meaning the hose chokes off internally and restricts or stops the oil flow) At this point you will need to do some pressure checks. System pressure should be 260 -290psi. Check this at the plug on top of the filter housing, at 2000rpm.
Can these checks be done with the belly pans on or can I go through floor pans?
And would I do that at the trans filter or suction filter?
See number 10, in the picture, the transmission filter. I think you can do this all from the topside.
Do I run it keeping an eye on the gauge, and when it gets hot? I'm Doing it Sunday
In short, yes. Since you said it works until it gets hot, monitor the pressure when you first start, after 20min of work and then again when its stops working. I would expect you will have a lower pressure reading after you have worked the machine. If your pressures are too low from the very start, check items 8 and 9.
I'll post an update as soon as I find a gauge.
Definitely a pressure loss. I was on key when I first fired it up. After operating it 15 to 20 min pressure dipped to a max 150 psi at 2000 rpms and only 100 psi at idol. Where do I go next?
When the pressure drops, is the pressure consistant with the steering levers in high, low, and neutral? Forward and reverse? As sheepfoot said, remove the bolts holding the pto cover on and check the three steel oil rings. Also check the inside of the pto cover for grooves worn into it where the oil control rings ride. If oil is leaking at the pto shaft, it has to get past the oil control rings first. Thats where I would start. Good Luck
Yes , it looses control the same in both hi and low forward left and right. In reverse it seems to operate normally. My rear pto leaks pretty good. It leaves a snail trail. I've put speedy sleeves in but it still leaks. New charge pump and all hoses under belly new.
Reverse acts up a little bit
How about fluids? Is TCH "required", or will the TSC 303 brand work as well in the transmission?
well pulled the pto cover off and noted that two of the three seal rings on the shaft were broken. The cover was groved on the inside from the rings. Long story short, new seals are ordered and I'm having the cover sleeved. I'll keep this updated until I find my problem.. Hopefully I didn't damage anything else while running it in this condition.
Grooves
Grooves in the cover J
Did this fix your issue ?