I have an older D-4, 1951 serial 7U12164 that I've been using to clear land for a home site. This morning I encountered a new problem. Coming down the hill after yarding a load of brush, burn ban in effect, the cat felt like it was out of gear, no engine braking. At the bottom of the short grade it stopped, clutch still engaged and in gear. Clutch snaps in and I've always snapped it in when at idle. If I hold slight pressure on the clutch I can move the cat, but if I lock the clutch in it stops. Prior to this problem I was able to lug the engine down, in other words it came on sudden with no warning. Suggestions?

Thanks in advance,

Kinda sounds like the teeth have been knocked off the clutch friction disc.
Take the 4-bolt inspection cover off and have a look. The disc is a pressed composition type material with somewhat fragile teeth and this happens far to frequently.

If that was the case why would I be able to move the cat by slipping the clutch, just puttng slight pressure on but not locking the clutch in?

That is odd but I believe that will soon quit functioning. Probably just enough material in the slightly less worn area to catch. Try putting a load on it and see what happens.

Damm!!

I was hoping for an easy fix. I'll let you know what I find.

clutch may be gone, but I would suggest, that if it drives the machine at all, the teeth on the outside of the disk are there. the sudden nature of the failure does point to the loss of the teeth or some major part of the clutch engagement "package", but I question how much "snap" is still felt while engaging the clutch?

I expect the reason the use of slight pressure to make the clutch engage is because the over-center/snap-in nature of the mechanism means that the clutch disk is compressed the tightest just as the linkage snaps over center and then it releases slightly, maybe enough to let it slip.

Maybe you can adjust the clutch and get it to go, or you may find the lock has backed off and allowed the cluch adjustment to move suddenly.

Do you know how to adjust it? I know it has been discussed before on the board(s).

Adjust it up a bit. If you can make it drag just before it goes over center it should have at least one more adjust left. You put max pressure on it just before it snaps over center so if it drags there is something left.
Later Bob

Yes, I know how to adjust the clutch. I've worked the machine hard and have had to adjust the clutch a three times in the last couple of months. It just surprised me that this came on in a no load condition.

There is a slight chatter now when I try to engage the clutch, almost like the throwout bearing fails under load.

Doesn't matter whether its in gear or not. Also the clutch seems to pull harder than before.

Had a similiar problem this summer with my 7U doing almost the same thing. Turned out it lost the the bottom bolt that holds the yoke to pivot shaft. The tabs on the lock washer broke off and the bolt backed out. Clutch wold snap over but felt wrong and the tractor would move if you held clutch lever back. I took off air cleaner for access through top but also had to go through bottom inspection plate, it was a tight fit around the belly pan. Mike.

When the clutch disc looses its teeth you also loose the centering when the clutch is disengaged allowing the disc to drop to where it may catch the flywheel teeth for a short while. This loss of centering also effects the clutch adjustment which you are experiencing. Sorry;) but all the symptoms are there.