Clutch problem?

I'm using a D4 (sn7u37530) for clearing brush, and when you first start running, it pushes fine. After it gets warmed up, you notice that the drive starts to slip a little as you push a pile. The longer you run, the more it slips, but I have never run it long enough to see if it stops moving altogether. When cold, you can pull the engine down some, but later, it just quits moving, without changing the engine rpm. Would anyone have ideas where to start looking, or any adjustments to make before tearing into it?

Thanks,
JD

PS,
I posted in the wrong forum earlier,sorry

Maybe it,s just a case of adjusting it. It needs to snap over center with a pretty good snap to be right.Is it an oil clutch or dry? If it,s oil maybe change the oil and fill to the correct height and adjust it if as I said it doesn,t snap over pretty good.

Could be transmission clutch like SJ says and it probably is, but could also be steering clutches, though it would have to be both at once. If the steering clutches are in need of adjustment, there will be very little free travel when you pull the levers, should have around 3 inches at the bottom of the grip in the levers. If it's the transmission clutch, you will have no snap as you pull it in and push it back out. It doesn't have to be a real heavy pull, I believe the D2 calls for something like 35 pounds pull to snap it in.

Later dry clutches were adjustable from the top through a larger top cover opening as were the oil clutches if you have one of those. The older dry clutches with the smaller access covers were best adjusted from beneath so that the lock bolt could be tightened securely. It would be a good thing to adjust it before it winds up stuck in a spot where you can't get underneath and have to have spagheti arms to reach in there.

You might also want to make sure if it's a dry type, it isn't being oiled as the tractor runs. There will be a drain plug in the clutch housing to drain any water and oil that have accumulated in the clutch housing. Dry clutches have a slinger to keep any oil from the rear main bearing from getting onto the clutch disk itself, but it will accumulate in the housing over time.