PTO Disengaging problemo

[treesitter]

Greetings all. I've been having an issue in recent weeks with my PTO disengaging every 100 yards or so. It started last fall but procrastinated on it since I didn't need the mower deck for a while but of course it didn't fix itself unfortunately. It just keeps popping out of being engaged, but the PTO lever does not go into the fully disengaged position. So I hit the clutch as fast as possible and quickly put the PTO lever in the disengage position, wait for the PTO to stop spinning, engaged the PTO again and all is fine, for about a 100 yards or so.

Perhaps related (don't know), but I am all prepped to split the Cub tonight to put in a new throw out bearing, which I've done a few times in the last several years. I am beginning to wonder if I have slightly bent spline or something causing my throw out bearings to prematurely get worn too fast? And could that same issue be causing the problem with the PTO? Or something? I plan to take the PTO cover off and the transmission cover off while I have things torn up anyway to take a looksee; but I have never removed either so I am blindly going to look for anything obvious and I have never messed around with anything related to the transmission and/or PTO. But if anyone can indicate what potential problem spots I should closely look at I would appreciate it and/or you best educated guess what the likely culprit(s) may be. Which I know could be a tall order. I can certainly take pics once I have covers off. It is one area of the tractor (PTO/Trans) that has never had any work done on it since, who knows, 1948?

Thanks, Andy

[Waif]

Two different shafts. Coupled at rear when P.T.O. shifter moves "pto clutch" to join them.
The pto clutch is more of a coupling. Subject to wear at end of shifter lever that engages it. But a look see would tell more.

Clutch throw out bearings can benefit from an extended soaking/oil bath before installing.

You two issues should be treated as seperate. Though if a shaft can move , it can disengage/change a proximity to one it couples to...

[Bob McCarty]

Remove the fill plug on the top of the tranny and with a flash light look at the pin on the end of the PTO shift lever (lower left in picture).
If it is worn in half, it keeps the clutch from moving forward enough to engage the splines. If worn, it needs to be replaced. Hopefully the splines on the end of the drive shaft are not worn too badly.

[treesitter]

Thanks to both of you. I ran out and took a look at the pin at the end of the PTO shifter lever and it looks pretty solid. I was thinking about that and hoping for it as it seemingly would be an easier fix. But it looks full length and pretty good. There is a little play on the larger pin in the picture above that actually connects to the PTO shifter; it moves in/out some. But doesn't seem to be enough to cause a problem; maybe an 1/8". But maybe that's enough play to give me a problem...? I can put a couple washers on it to space it out to where it is nice and snug. Of course there is one behind the cotter pin but I can probably fit a couple more flat washers in there; at least one more. I tried to take a picture through the fill plug hole but that didn't work out. The splines on the end of the shaft looked pretty good too as near as I can tell.

I will treat as separate issues. The throw out bearing I am about to install tonight has been soaking in oil for at least a couple years- I bought it as a back-up. So I will get the bearing in and get all back together then turn my attention to the PTO, since I can't test anything until then. And that area has the steering post, pull rods, etc laying around and on it so to split it....

Thanks for your responses!

[Dale Finch]

Another thing to check with the PTO...grab the shaft where it sticks out (or a pulley, if one is mounted), and see if there is ANY forward/aft movement. There should be none. If you can pull/push the shaft at all, the bearing inside may have shifted. It's a fairly easy repair. Let us know what you find. It's just one possible problem.

If you are not positive the pin on the shifter is DEFINITELY good, you can remove the PTO without draining the transmission, and see it more clearly...the pin must be round, and NOT have a flat side.

[treesitter]

Thanks Dale. Ran out to check that and there is just a tiny amount of play there, maybe 1/16" at best. But I also found out my pulley was sliding on the shaft. It wouldn't slide all the way off, but I could move it back and forth at least an inch or so. I probably will pull the PTO and check it out closer after get things back together from the split. The pin on the shifter didn't have a noticeable flat side on the sides or top, and the end looked pretty flat. And I assume a flat side would be unlikely on the bottom.?.? But, as you know, it is not the best view through the filler hole.

[Jim Becker]

Another thing to check with the PTO...grab the shaft where it sticks out (or a pulley, if one is mounted), and see if there is ANY forward/aft movement. There should be none. . . .

Likewise, there should be essentially no end play in the transmission input shaft. You can check it while you have the tractor split for the throw out bearing. If there is end play in the input shaft, the retainer at the front of the transmission may have been installed backwards.

[Glen]

Hi,
Below is the Cub service manual, if you don't have it. It has lots of info.
I would read section 6A, the PTO section, if you have never repaired a PTO before.
Disregard the info for the Belt Pulley Unit if you don't have one.

http://farmallcub.com/rudi_cub/www.clea ... index.html

Below is PTO info, if you need it.

Sometimes I have needed to remove the bolt holding the PTO shifter guide to the corner of the transmission shifter cover, so the PTO shifter can go farther ahead, to remove the PTO out the rear of the housing. The PTO can be sort of locked in by the shifter pin if the lever won't go far enough ahead.

They have said to check the PTO pilot bushing also, it is in the rear end of the clutch shaft, sometimes they are wornout and need replacing. The front end of the PTO shaft goes into the bushing, the end of the shaft should be smooth.
TM Tractor has a new PTO pilot bushing, and other PTO parts.

Below is a pic from TM Tractor of the transmission front seal retainer. The clutch shaft goes through it at the front of the trans. The side with the bulge has to face to the rear, into the trans.
If it is backwards, there can be about 1/4" of end play in the clutch shaft, and the shaft can move forward.
The PTO is driven by the splines on the rear of the clutch shaft.
The PTO can slip out of engaged if the clutch shaft moves forward.
The 2nd pic is the front of the trans.

You can look in the housing with a light, and see if the retainer has the flat side forward, or the bulged side forward.
I have seen on here that some of the old retainers were not totally flat on the front side.

Also turn the clutch shaft while the Cub is split, and see if it is straight.

The PTO shaft on many earlier Cubs was held in place at the PTO ball bearing with staking.
Sometimes the staking fails, and the PTO shaft can move to the rear some, that will let it slip out of engaged also.
The 3rd pic below shows the PTO.
Look at the amount of shaft sticking out of the housing where the oil seal is, that is where you can see if the shaft has moved to the rear.
The shaft may be tight in the bearing and need to be hammered in again.

The 4th pic shows the PTO shaft, and the ball bearing, the bearing has to be on the shaft fully to where the shaft changes sizes, there is a shoulder there.

The 5th pic below shows the staking. There are about 3 stakes spaced equally around the shaft.

I would grease the front end of the PTO shaft when you put the PTO in the housing.

[Rick Spivey]

There is a little play on the larger pin in the picture above that actually connects to the PTO shifter; it moves in/out some. But doesn't seem to be enough to cause a problem; maybe an 1/8". But maybe that's enough play to give me a problem...? I can put a couple washers on it to space it out to where it is nice and snug. Of course there is one behind the cotter pin but I can probably fit a couple more flat washers in there; at least one more.

As I read this I am a little concerned that if your shifter is moving outward ( or you pull it outward with more washers), then the small pin will have less engagement with the collar on the PTO clutch, and will cause it to engage the splines on the input shaft less. It is a bit of a circular motion that pushes the clutch up onto the input shaft splines, and if moved outward, the smaller pin will effectively have less arch to move the clutch with.

Further investigation of the shift lever is probably warranted.

[treesitter]

Thank you all- great info. I miss-stated the PTO shifter lever issue (perceived issue that is). It appears ok. But upon further inspection of the pin on the end that moves the PTO clutch/coupling through the fill hole, it does appear to have a flat side on the rear, which made it harder to see through that little hole at that angle. Better glasses helped too! But I got the throw out in and ttactor back to together from the spli. The clutch fingers also needed adjustment- they were all at 1 1/8" instead of 1 1/4".

Thanks much.

[treesitter]

Question- can a new PTO shift lever be installed through the hole it goes into or does the rear cover have to come off?

Thanks

[Bob McCarty]

Only the triangular shaped cover that the shaft goes through needs to be removed. However, I had my wife (with smaller hands) reach in to insert the new lever. The rod goes almost up against the casting in the front and it needs to be parallel with that surface to get the rod through the hole.

[treesitter]

Thank you!

[Glen]

Hi,
If you have had the Cub split at the clutch area, you didn't say if you checked to see if the clutch shaft moves forward and rearward, or if you looked in with a light to see which direction the trans front seal retainer is facing.

The PTO shifter part Bob posted the pic of above goes in or out from inside the transmission housing.
You have to remove the PTO out the rear of the trans housing to remove the Lever and Shaft, TM Tractor calls it.

The PTO shifter lever is on the end of the Lever and Shaft.
You have to remove the PTO lever to remove the Lever and Shaft.
There is a cotter key at the bottom of the PTO lever, below the spring, remove it and the lever comes apart.
Below is a new Lever and Shaft at TM Tractor, if you need it.

http://www.tmtractor.com/new/pt/317fp.htm

TM Tractor has other new PTO parts.

I would check the PTO drive splines while it is apart, in the PTO clutch, and on the rear end of the clutch shaft.
It's easy to replace the PTO clutch while it is apart, if needed.
If the splines on the rear end of the clutch shaft are not good, then you need to split the Cub to replace the shaft.

Below is a pic of inside a Cub trans housing with the PTO out, and the rear cover off.
The PTO Lever and Shaft is not in the housing, in the pic. It goes in the top area, near the rear end of the clutch shaft, which is in the pic.

The 2nd pic below, from TM Tractor, shows the PTO drive splines on the rear end of the clutch shaft, and the PTO pilot bushing in the shaft.

[tldec50]

Now is a good time to check your splines that the pto coupler/clutch mates with.Being worn will kick it off like you explained . I had to change my main shaft doing the same thing.thanx,Ti m