L3750 Shifting Problems

[Davaron]

OK, I have a shifting problem. Checked the archives and did not finds a suitable reference. I have a 1987 L3750. It has the the gear selection on the right side of the seat and the hi/lo and forward/reverse on the left. Tractor is stuck in 2/6 gear. Shifter will not move out of this gear. Tractor runs fine and will operate in either 2nd or 6th gear depending on the range and it operates forward and reverse. It will just not come out of 2/6. PTO works as well.
Any suggestions? Thanks or any help.

 

[brain55]

Yes, you have sheared the roll pin on the main shifter lever, very common failure. Remove the seat pan and the sheet metal around the shifter on the right side of the seat. The remove the shifter housing. You'll have to line up the shaft, the shifter, and the breather hole, then drive the pieces of the broken roll pin out. Kubota had upgraded those parts years ago to a solid pin. Instead of buying the Kubota parts I just drill out the shifter and shaft to 1/4" and use some hardened rod from the hardware store cut to length. Then I cut my own cir-clip groove in the shifter to keep the pin from being able to fall out. You'll probably have to talk to a pretty experienced Kubota parts guy for him to be able to get you the updated drawing unless Kubota has managed to put this in their electronic parts manuals, otherwise he is likely to just have the old style with the roll pin and safety wire.

Brian

 

[Davaron]

So you remove the 4 bolts from the housing and everything just lifts off? Sounds pretty straight forward. Any little hidden things to be on the look out for? Is there a casket to replace? I plan to use it as is for the weekend and then get parts the first of the week.
Thanks

 

[brain55]

The gasket is a square cut o-ring which you should be able to reuse, there are detent springs under the cover but typically they stay with the machine.

Brian

 

[Davaron]

Thanks so much for the help. I will let you know the outcome.

 

[Davaron]

Ok, Turns out that the roller pin was bad but the worst of the deal was that the shifter rod itself was seized up in the housing. No lub could free it so I had to purchase a new housing and roller pin. $300 and we are back rolling. Moral of the story... Keep your tractor sheltered. Moisure seems to have been the culprit.
Thanks for all the help

 

[SRTractor]

I recently had a similar problem with my son's L3750, but after following your instructions, I find that the roll pin is not broken. Also, I can line everything up & put it back together and it will shift a couple of times, then nothing again. It's as if the shifter mechanism is missing something to keep everything lined up. Any insights?

 

[rbargeron]

Sounds like another pin or a detent is causing a hang-up. Each side needs to click into the centered position for the other to move. If the main pin is ok, check the other pins, rails, detent balls, springs etc. If you're lucky no parts will drop into the case

 

[SRTractor]

Thanks rbargeron, but I checked the forks, and their pins as well. If one is very careful lining up the neutral position, you can proceed to the next gate, but it's almost as if the shifter lever (inside) is not moving the slide far enough. It doesn't appear to be bent or excessively worn. Just general wear maybe?

 

[rbargeron]

What are the symptoms on this machine? I've often gone right by something that looked ok - but wasn't. How's the top shifter shaft for wear and/or rust? Keep looking, you'll find it.

 

[SRTractor]

Top shifter shaft has no rust & appears to have no discernible wear, although a mic may reveal more than the naked eye. If you try to shift from the left to right gate, or vice versa & are not careful, it seems to go to never never land and the shifter will no longer change any gear. If you go carefully from one to the other, it will shift, but seems to hit the end of the H pattern before fully engaging and will just grind. If you are just a bit more forceful, it will engage the 3/7 & 4/8 gear & once engaged the gear functions fine. Thanks again

 

[rbargeron]

Maybe unscrew the gate plate and watch how the linkage moves (or doesn't). When it hangs up how do you get it back - take something apart again?

 

[SRTractor]

I have done this, and the forks move smoothly as long as the gears are lined up. The problem seems to be the shifter itself. Sometimes when it jams you can work the shifter around & it will re-engage, but I have had to remove the shift mechanism & realign it. That can be a major hassle. I just can't see how it is getting out of it's proper alignment.

 

[rbargeron]

hard to be much help from this distance, but there has to be a clearance or interference somewhere that isn't right.