L4150DT Hydraulic Shuttle "slipping"

[JWR]

I suspect rebargeron is correct. Just for a side story (probably unrelated) the B2150's had a latch that had exterior teeth and allowed one to hold the clutch from fully engaging. The teeth allowed you to select how much if at all the clutch engaged. Small lever on the side of the chassis. The service manual says it was for convenience in doing maintenance. It got inadvertently latched part way one time and I could not move the tractor. Went thru all manner of panic thinking the clutch had gone out and finally found that silly little latch.

 

[gpsmatty]

I had a L4150 with hydraulic shuttle for a few years - one of the models Kubota built its reputation on in the U.S. - great tractor. (I now have its brother L5450)

The symptoms say its the main clutch that needs adjustment, not the shuttle valve linkage.

There should be about 1" of pedal free play before the clutch starts to feel heavier (starting to disengage). If tapping the clutch pedal stops drive and pto, the PEDAL linkage under the left floorboard needs adjustment.

The turnbuckle 030 in the diagram needs to be adjusted so there is 1" free pedal play. That should restore motion with pedal up.

You may find that with the clutch pedal correctly adjusted, the pto will no longer disengage with the pedal full-down. If so, post back and we'll go from there. Best luck - and Happy New Year ! Dick B

I did mess with the adjustment and ended up disconnecting the rod altogether to take the clutch adjustment out of the equation and it still slipped. I went on ahead and ordered a new single-clutch disk kit.

 

[rbargeron]

This rig sitting so long, strange conditions can develop.

Another possibility is that the release bearing and/or fork has become stuck in the near-released position and won't move back enough to fully apply the pressure plate, clamping the clutch and engaging the drive.

Does the clutch pedal move down freely now? Is it hard to push? If so it could be hanging up on part 080.

I'd try using some extra force to try to get more travel in the release direction. See if the clutch lever 110 or 060 or 040 will move back further - like lifting the clucth pedal but using more force directly on the lever to move it back. If it's not stuck too bad it could free up, saving a machine split.

p.s. glad you mentioned it has the single clutch - the pto adjustment on a 2-stage would make this less nice to fix. Dick B

 

[gpsmatty]

I went on ahead and did the clutch, the clutch in there was toasted.

It's a lot better and obvious that the single disk clutch was slipping badly, but I am still having some slipping issues in higher gears and it's for sure not coming from the single disk clutch as the PTO still spins when it's slipping.

At this point, I think it could be some kind of internal hydraulic seal leaking, problems with the priority valve, blockage somewhere?

Another variable is there was a lot of metal on the drain plug:

I also noticed what seemed to be a lot of metal in the oil that dripped out of the 3 shuttle lines that I took off the transmission. Another thing to note is there are no issues with the loader, it has plenty of hydraulic power. I just want to check everything I can before I pull it back apart to replace the shuttle clutches.

 

[rbargeron]

Glad the pto is squared away.

Can you tell if the remaining slippage is the same in forward and reverse? If not, the remaining slipping might be shuttle disc wear or skudge in the control valve (priority valve would affect both the same.)

For working on the shuttle, there's a thread here that might be useful to look at. Its the later version of the clutch pack they called the "ever clutch". Your assy is similar - the L4150 WSM has the disassembly, inspection, and measurement of the earlier one. Looks like it comes out the back of the clutch housing.

Best luck - and work safe, Dick B.

 

[gpsmatty]

I checked the flow priority valve and there didn't seem to be any blockages and the plunger moved freely.

Next up I checked the 2 plungers in the shuttle shift where you can add extra shims for more pressure and this is what I found..

So many extra shims were put in the cap that wouldn't even screw down all the way before bottoming out, I removed 2 shims and there was no difference in performance.

On this plunger, there were 3 shims and a couple of lock washers..

All this tells me the PO was having slipping issues and either they or their mechanic tried to fix the problem by adding a bunch of extra shims.

I did test the pressure off of the top plug on the shuttle valve and was only getting about 50PSI in forward, but I realize I should be testing pressure from the plugs in the back, which I am planning on doing later today.

rbargeron​

To answer your question it feels like it slips more in reverse, but that could be my imagination. And that's good news I can split the tractor at the next "seem" back to access the shuttle clutch packs. I am fully prepared to tear it apart and replace the clutch packs, but want to test everything I can first to make sure it's not some kind of a pressure issue.


One thing I was wondering is if it would damage anything inside the trans not having a lubrication circuit pumping by pulling the feed line off the shuttle valve and testing pressure directly out of the priority valve, but if the pressure checks out testing the forward/lubrication/reverse circuit than I know it's not a priority valve issue.

 

[5030]

If the pto turns when not engaged, the pto brake is shot.

 

[gpsmatty]

If the pto turns when not engaged, the pto brake is shot.

I have not been able to verify if the L4150DT has a "neutral" for the PTO, but once I get all the shuttle shift issues figured out, I am digging into the rear section of the gearbox/rear end and replacing the brakes and anything else needed.

 

[5030]

The PTO pack is only accessible with a split. There is no 'neutral'. Only on or off or IOW pressurized or not.

 

[gpsmatty]

The PTO pack is only accessible with a split. There is no 'neutral'. Only on or off or IOW pressurized or not.

There is no PTO "pack" on this tractor. There's no way to disengage the PTO independent from travel. Just the single disk clutch to disengage. I am no longer having PTO issues after replacing the single disk clutch. Furthermore, you can remove the PTO case from the back and do not have to split the case.