John Deere 2520 - Rear PTO & Rear Implement Shaft Overlap

[larry8818]

Hello guys,

I recently converted my Bearcat 73554 Chipper/Shredder over to be compatible with my I-match hitch. By doing so put the unit back about 4-5". Right now I am only getting about 2 1/4" - 2 1/2" overlap of my PTO shafts. The book does not state what this length should be, only that the distance between the two shafts should be 24 1/2" or less, and if not contact my dealer and get a longer shaft.

Since this is my first implement with a rear PTO drive shaft, and I am well over the 24 1/2" as you'll see in the pictures, I am looking for some of you with more experience to tell me if they know this will be fine or destined for failure. I have about 3 hours on the machine now with the stated overlap and no problems yet.

 

[TedLaRue]

I think you're asking for trouble. I recall the manual for one PTO shaft I have stating clearly that the overlap should be 1/3 the total length of the shaft. The Bush Hog manual says at least 6". That seems reasonable to me. Your 2-1/2" seems way too short to me. I wouldn't want to be around if that joint starts to buckle at 540 RPM.

True, there's no reason for it to have lateral stress....unless something is a little off balance, or a little off center, the joint wears and becomes off center, etc...

The power of your tractor is transmitted from the PTO to your chipper through the overlap. If your overlap is a lot shorter than it needs to be, then the wear on that overlap will be much greater than it should be. A little wear, things start loosening up, the shaft is not centered any more, and then the power of your tractor is whipping half of a PTO shaft around at 540 RPM....

You've got the added concern that you'll be near the PTO driving your chipper. It's not like you're using this PTO on a brush hog behind you.

My recommendation is to get the right length PTO, and try to sell yours through your local "bulletin board" paper or on EBay.

 

[RoyJackson]

Another thought is to get a PTO Extender, depending on how "well over" the 24.5" you are.
You can buy these at Tractor Supply and online.

 

[madpogue]

Seems to me this is a case of "the more the better". It's not like a mower or tiller, where you'll be running the PTO while driving the tractor and implement over uneven terrain. In those cases, you can be sorry with either too much or too little overlap. But with a chipper, I would def. go for as much overlap as you can manage, and indeed, at least 6". The "one-third" rule, BTW, means 1/3 of _either half_ of the shaft. Once you put it together (do the math), it translates to 20% of the overall shaft length. So for your 32"-ish overall length, I'd go for 6-7" of overlap minimum.