Clutch/PTO Issues while snow plowing

Mon Feb 17, 2014 5:33 pm

About 4 years ago, I replaced the clutch, pressure plate and TOB on my '66 Lo-Boy. It has worked well, more or less since then. Very rarely, usually when mowing in thick or tall grass, if I would stop, disengage the PTO and put it in reverse, the PTO would engage on it's own when I let the clutch out to go in reverse. After some fiddling, it would be OK and I would continue.

This past weekend, I was plowing some snow, which was deep and heavy for about 2 hours. A little ways into it, I depressed the clutch to change from a forward gear to reverse, the tractor stopped (as expected) by when I tried to put it into R (and subsequently any other gear), gears just ground. I also looked back and noticed the PTO was spinning although the lever was not engaged. I lowered the throttle to idle, clutched, moved the pto engagement level back from disengaged to engaged to disengaged, the PTO stopped, then I proceeded to plow. I never had any more grinding gears after that one incident, but the PTO was spinning one or two other times.

What do you think is broken or worn out?

Thanks again in advance.

Re: Clutch/PTO Issues while snow plowing

Mon Feb 17, 2014 5:47 pm

probably the pin on the arm that engages the PTO gear is shot, take the filler plug out for the transmission and look in the hole with a light, you can see the arm and where the pin rides in the middle of the gear,move the PTO handle and you can watch the gear engage and disengage, the pin rides in the slot and is most likely worn off

Re: Clutch/PTO Issues while snow plowing

Mon Feb 17, 2014 6:17 pm

One other thought comes to mind. Your bearing retainer for the front transmission seal on the upper shaft may be installed backwards. That would allow front/back movement of the shaft which may contribute to the symptoms. Even if the retainer is backwards, you would probably still have to have the problem tst described to get this behavior.

You may also have a problem with the clutch plate hanging on the input shaft or a dragging clutch pilot bushing. Your symptoms seem to require multiple issues at the same time.

Re: Clutch/PTO Issues while snow plowing

Mon Feb 17, 2014 8:42 pm

Thanks for the tips! If it is the pin that is worn, can it be replaced by removing the cover/shifter or does it require a split?

Re: Clutch/PTO Issues while snow plowing

Wed Feb 19, 2014 9:58 pm

I would think that you could remove the pto from the rear of the transmission housing, pull the pto shifter lever, and take the shifter out through the inside. I've never done it that way though. Maybe the ring gear would be in the way? Another reason for your pto to spin might be the pto shaft binding on the pilot bushing. I don't know why it would do that, but it would cause the problem you are describing, if the pto got wound up while you were moving, and continued to spin the main shaft when you pushed in the clutch.
glenn

Re: Clutch/PTO Issues while snow plowing

Wed Feb 19, 2014 10:32 pm

The shift arm can be changed by just pulling off the back cover, its pretty easy, remove bolts and pop it out as an assembly

Re: Clutch/PTO Issues while snow plowing

Thu Feb 20, 2014 9:18 am

tst wrote:The shift arm can be changed by just pulling off the back cover, its pretty easy, remove bolts and pop it out as an assembly
It is also easier if once the pto and cover are removed you roll the tractor enough the differential is horizontal, which will give you more room to get your hand in there. From previous experience I suspect you will find, possibly among other things that the pto pilot bushing inside the end of the transmission shaft is worn, maybe completely gone, and the pto shaft is binding on the transmission shaft.