L4150DT Hydraulic Shuttle "slipping"

[gpsmatty]

I just picked the tractor up, PO had health issues, and it sat for five years until he passed away, and I purchased it from the estate. I changed the oil, flushed the fuel, and put a new battery in, and the tractor fired right up (huge relief). The 3 point lift works bucket lifts and has enough power to lift the front wheels of the tractor, but it won't go anywhere unless in the lowest gear. The best way I can explain it is it feels like it's slipping. My automotive experience and knowledge tell me it doesn't quite feel like a burnt-up clutch.

At this point, I feel like I've read everything there is to read on similar issues, and this:

https://www.justanswer.com/agriculture-and-farm-equipment/enhty-l4150-kubota-hyd-shuttle-want-move-forward-reverse.html

That site sucks, and there is no resolution to his problem, but that's precisely what I am experiencing.

It's raining today. Otherwise, I would be out working on it, but my first course of action is to replace the hydraulic filter, and look for some kind of adjustment on the shuttle valve.

Curious what else I should look out for, and what the best way to definitively figure out if it's the clutch or not.

 

[gpsmatty]

I'm thinking it has something to do with 4 and 7 in the first drawing. Or 17, the flow priority valve?

 

[gpsmatty]

I had someone watch the PTO, and when it starts slipping, the PTO doesn't turn, and the tractor doesn't go anywhere, leading me to believe it's the single disk clutch and hopefully has nothing to do with the hydraulic clutch.

 

[big bubba]

not sure my hyd shuttle is the same as your model. i started experiencing the same problem, seemed as though it was not fully engaged, etc. there is a turnbuckle affair on mine that you can fine adjust the hy shuttle cable for either direction. mine is on the column.
so i'd try to adjust the hyd shuttle cable 1st. that didn't solve the problem on mine so i took it in. the hyd shuttle cable was sticking. access to it is a chore (have to drop tank, etc). wish there were some lube points on the cable. cost me 1k repair bill. hopefully yours can be remedied by adjustment. but sitting that long, the cable might be sticking
good luck

 

[gpsmatty]

not sure my hyd shuttle is the same as your model. i started experiencing the same problem, seemed as though it was not fully engaged, etc. there is a turnbuckle affair on mine that you can fine adjust the hy shuttle cable for either direction. mine is on the column.
so i'd try to adjust the hyd shuttle cable 1st. that didn't solve the problem on mine so i took it in. the hyd shuttle cable was sticking. access to it is a chore (have to drop tank, etc). wish there were some lube points on the cable. cost me 1k repair bill. hopefully yours can be remedied by adjustment. but sitting that long, the cable might be sticking
good luck

I went on ahead and checked it again, on my model it's on the backside of the firewall and has a rod going directly to it. I disconnected the Rod and manually moved the shuttle to make sure it was fully engaging and unfortunately there was no change. The fact the PTO turns off when it starts slipping leads me to believe it's the main clutch. What concerns me though is when it's cold it wants to barely move at all and the second thing is I cant smell any burning clutch.

 

[the old grind]

If 17 sticks flow will go through open center valves to tank, no pressure for HST but stalling a cylinder (curl up & hold) should divert full flow to HST. If it doesn't I suggest 17 isn't the problem. I also think if it was 4 o 7 one direction wouldn't work, but both?

 

[gpsmatty]

If 17 sticks flow will go through open center valves to tank, no pressure for HST but stalling a cylinder (curl up & hold) should divert full flow to HST. If it doesn't I suggest 17 isn't the problem. I also think if it was 4 o 7 one direction wouldn't work, but both?

I agree, after further diagnosis and research, I believe it's the single dry clutch between engine and transmission. I think this because when traveling forward and it "slipping" the PTO is not turning.

 

[the old grind]

Could it be as simple as checking an adjustment on the dry clutch? Fingers crossed.

 

[gpsmatty]

Could it be as simple as checking an adjustment on the dry clutch? Fingers crossed.

I removed the rod altogether so there was no "adjustment" pressure on it and it was no different. I did notice that if I tap the clutch while moving forward it disengages with just tapping the clutch as if there's no play, and that was even after checking adjustment. At this point, I've got a clutch kit on the way and am going to change it out.

 

[rbargeron]

I removed the rod altogether so there was no "adjustment" pressure on it and it was no different. I did notice that if I tap the clutch while moving forward it disengages with just tapping the clutch as if there's no play, and that was even after checking adjustment. At this point, I've got a clutch kit on the way and am going to change it out.

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

 

[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.