M4950 PTO Shaft

[chasdabigone]

Hey guys, i got a m4950 at auction and it is missing the PTO drive shaft and most of the components that attach to it. How can I tell that the drive shaft coming from the engine works (circled in red in the first pic)? Is it ok to crank the engine over and see if it turns? Obviously the PTO drive shaft has been removed for a reason so I want to make sure it will work before I buy the parts to repair it. I took some pics of the inside of the PTO gearbox. It has some damage like the PTO drive shaft got messed up. I think I will try and put a new one in if the rest seems ok.

 

[rbargeron]

The visible end of that shaft (coupling?) looks a little beat up. Unless you can get eyes on the gear(s) that drive it, it won't be possible to know all the parts needed to reinstate the pto. It's likely whoever took the old parts out verified things still turned ok without them, but whether the other parts will still operate under load is a guess at best.

I once replaced two broken gears in a transmission but didn't notice that a third one was cracked. After it was all back together and re-installed, it blew up on the first test drive DOOH! Hard but lasting lesson. Good luck, Dick B

 

[chasdabigone]

I'm thinking my best bet is to prepare for and split the tractor at the spot where the transmission / clutch housing meets the PTO drive shaft. My other option would be to try to install the PTO driveshaft without splitting the tractor and see if it works, then split it if I still have problems. What would be the better option? I'm afraid of splitting the tractor but willing to try if I need to. Can I go in through the top on this to get to the PTO shift fork? I think it may be bent

 

[rbargeron]

I haven't worked on a M4950 so I can't say. A shop manual for it (or related model) may have enough info and pictures to tell how it comes apart. Replacing the missing parts and roll testing might indicate whether something further in needs attention. Or finding a whole used transmission might be an option?

 

[chasdabigone]

I've been up and down the shop manual for it but it is very hard to follow and understand - the parts manuals online are much better. I think I have to go in through the top after removing the hydraulic cylinder. It seems like an involved job but not too hard if I can get my engine lift high enough. I cranked the motor to see if the drive shaft spun and it does, and I also tested the PTO clutch to see if it works and it does (stops the drive shaft from spinning).

I can't get any leverage or to the area in question from the side hatch, which really leaves only the top. After looking thru the parts manual, I don't think I could get to the spot I need to if I split the tractor. Anyone pulled the hydraulic cylinder off the top of a transmission before?

 

[Dave M7040]

Hey guys, i got a m4950 at auction and it is missing the PTO drive shaft and most of the components that attach to it. How can I tell that the drive shaft coming from the engine works (circled in red in the first pic)? Is it ok to crank the engine over and see if it turns? Obviously the PTO drive shaft has been removed for a reason so I want to make sure it will work before I buy the parts to repair it. I took some pics of the inside of the PTO gearbox. It has some damage like the PTO drive shaft got messed up. I think I will try and put a new one in if the rest seems ok.

It looks to me in your first photo there is a round shaft just below your red circle that has sheared off. If so, this is serious damage and no telling what the broken pieces have damaged as well.

Gears and shafts are expensive parts..

Likely the previous owner broke the machine, took it apart enough to see it was badly broken, left out the broken parts and sent it to auction.

It is hard to imagine what it took to destroy a shaft like that. Running a big bushhog and not having a shear bolt drive train. Or having a slip clutch that was so rusted together it did not slip

Depending upon the tractor's description at auction and how long ago you bought the machine, I would be going back to the auctioneers as this level of internal damage should have been disclosed at sale.

You may have a parts machine unless you paid a lot for it and can pay for the parts to justify your purchase price.

This link may or may not bring you into Messicks parts illustration for a M4950. The pto shaft is Approx $150, the gear another $150 + other bushings gaskets bearings etc.

Kubota M495�DT-S (Synchro-shuttle, 4wd) Parts Diagrams


The broken pto pieces may have been filtered before they reached the hydraulic pump, but maybe not if the filter was plugged and possibly bypassing. It is just another big unknown.

WSM's are not instructional or how to material but rather reference material for knowledgeable people who need to know torque spec's, relief valve settings etc.

Parts manuals make things appear amazingly simple as they show a limited amount of detail and also NOT what has to be removed to get to the parts you are looking at.

Dave M7040

 

[chasdabigone]

It looks to me in your first photo there is a round shaft just below your red circle that has sheared off. If so, this is serious damage and no telling what the broken pieces have damaged as well

That piece is the coupling that the shift fork moves back and forth to engage the PTO. It wasn't sheared off (i don't think?), the pic is just kind of blurry. It looks to me like the PTO shaft was removed because that shift fork got bent then the guy didn't want to go in and fix it. I have been using it around my land for a few weeks with no issues besides the PTO not working. The hydraulics work and lift pallets fine (which is why i bought it). I just thought I would go in and try to fix the PTO if I could and have a full working tractor.