Commercial 12 PTO issue

Pull to engage is normal.

It looks like you are missing some pieces there.

Take a look at the IPL.

If it fails to stay engaged, then it may be that the shift rod or bit of angle iron is bent or worn. Yes, the shift rod is what keeps it engaged, not the parts bolted to the advance casting.

Below are pictures of what keeps the PTO engaged (and disenaged).

The pictures I posted of the rod and the bit of angle iron can only be seen if the fuel tank is removed.

If your rod control is backwards, then the shipper shaft and or related parts are not installed correctly.
Before working on the shipper shaft, remove the battery box. It takes about 5 minutes to remove and will save much aggravation and time.

One more note. Never install an attachment with the PTO in the engaged position. Bending or breaking the shipper shaft is a near guarantee if you do.

here's a couple more pictures.









Richard-TX, are you saying the only way to examine what's going on is to remove the fuel tank and battery tray?

I agree with Richard, there just isn't enough room under that battery box to check things on the PTO.

But before you pull the battery box, remove what ever attachment, careful lots of oil in the chassis or at least there should be, and take a look at the shipper shaft while moving the lever. Maybe you can disconnect the long rod, if not have someone shift the PTO while you watch the shipper shaft.

Make sure the trunnion block is in place. OK, the pin on the bottom of the shipper shaft is offset to one side, this pin rides in the trunnion block to move the dog gear in and out.

The upper body, the 1 3/8" round with the pin sticking up which fits into the shifting lever, that big round part locks on the upper end of the shipper shaft on a special flat with a set screw, but it is possible to mount it WRONG.

To check the mounting of the shifter body, the pin of the body should be almost 180° out from the pin on the bottom of the shipper shaft.

Click to enlarge

Roger,

Richard,

Now we have to show Justapilot the two plate version. This is not what he needs, but he should be able to get the idea of the second plate on top.

http://s457.photobucket.com/user/beaner2u/story/5843

Roger,

If you remove the shifter body from the shaft, remember to set the .010" clearance between guide and body.

Click to enlarge

Servicing of the early PTO's is the same for your C12, just a different shift lever. The above service info is on page 25 of this manual,

http://gravelytractorclub.org/image...hind/model-l/Convertible_76_Serv_Man_1174.pdf


Roger,

Hi All, I don't mean to hijack the thread, but I am also having an issue recently with my PTO on a Gravely Commercial 12 unit. When I pull the PTO lever to engage, and then put the tractor into high gear, the blade on my rotary mower will rotate, but at a lower RPM than they usually does, and it just doesn't seem to have the same torque like it usually does. Eventually, it stops spinning all together, but the PTO lever is still engaged fully.

I pulled the mower off last night for a quick inspection and did not notice any teeth missing on either the gear on the tractor or the gear on the mower. The mower blade would spin freely when I rotated the gear. I also verified that the shipper shaft (I think that is what it is called) appears to be working because I could see the dowel pin on top rotate when I engaged the PTO (engine off). When this occured, I did note that it appeared to 'push' the gear forward, which I assume is how it engages the attachment.

Lastly, I did double check that the hi/low and forward/reverse levers were working as they should.

Any advice? Suggestions? The only other thing I can think to check would be the slip clutch on the mower deck to ensure it is properly tightened. Any help would be greatly appreciated. I apologize if my description was lacking, I haven't torn into this machine ever before.

Thanks!!

I would check the slip aka safety clutch. New clutch discs are available but tightening may resolve the issue. Tighten each bolt about 1/4 of a turn and try it. Don't forget to loosen the jam nuts before tightening and retighten them after adjusting the bolt. If tightening helps, you may want to replace the clutch disc.

Depending on what you use the 30" mower for, that safety clutch may need to be tighter than what the manual calls for. Too tight and you risk damage to the gearbox when something like a tree stump is hit.

"Hi All, I don't mean to hijack the thread, but I am also having an issue recently with my PTO on a Gravely Commercial 12 unit. When I pull the PTO lever to engage, and then put the tractor into high gear, the blade on my rotary mower will rotate, but at a lower RPM than they usually does, and it just doesn't seem to have the same torque like it usually does. Eventually, it stops spinning all together, but the PTO lever is still engaged fully.

I pulled the mower off last night for a quick inspection and did not notice any teeth missing on either the gear on the tractor or the gear on the mower. The mower blade would spin freely when I rotated the gear. I also verified that the shipper shaft (I think that is what it is called) appears to be working because I could see the dowel pin on top rotate when I engaged the PTO (engine off). When this occured, I did note that it appeared to 'push' the gear forward, which I assume is how it engages the attachment.

Lastly, I did double check that the hi/low and forward/reverse levers were working as they should."



Tony,

Does only the mower slow down, or does the tractor also lose ground speed?

If only the mower slows down, then I agree with Richard, the safety clutch needs tightening or new clutch discs. You say that the mower turns freely by hand so it does not sound as if something is binding in the mower deck.

Tell us more.

Roger,

Update! Great news, it looks like it was just my safety clutch that was too loose. I re-tightened to the appropriate specifications, and voila, mower engages perfectly now!

Now the bad news... I see I have developed a fuel leak on the bottom of the tank, and was dripping more than I'd like to see. I removed the tank and brought it to a local radiator repair shop, and he recommended replacement due to it rotting from the inside out. He said he could fix it and get it to not leak, but he offered no guarentees on how long before the next leak surfaces.... Any suggestions on where I can get a replacement tank for this unit, or even something that is comparable?

The new tanks from Gravely are most impressive. Very heavy gauge steel. A little smaller but not bad at all.

The best way to patch the tank is to solder a piece of .010 brass shim stock over the area. Do NOT use a torch unless you take all of the precautions necessary when dealing with a gas tank. Washing out a gas tank is a lengthy process and one that is not to be skimped on or taken lightly.