Kubota B1750HST won't move

[mmcdermott1]

Hello. I have a Kubota 1750 with HST and the other day i was riding through my field and the tractor just stopped moving. There was no noise or any indication at all that something was wrong or broke. The loader, 3-point, and both PTO's still work fine it just won't go forward or reverse. I checked all the linkage from the pedal and it is fine. I changed oil and filter although I just did this anyway and still nothing. I pulled both strainers as well and flushed. I pulled the back cover off of transmission right about rear axle and that all looks fine. I have not yet pulled the front top plate off because you have to split the tractor to get it off. This is the plate where the HI/LOW gear lever goes into. I am at a complete loss for what is going on. Any help would be greatly appreciated.

 

[ByronBob]

Did the linkage come apart from the foot pedal? Other than that I think the pump might have died if it only drives the transmission.

 

[RobertN]

My B8200 has three ranges. I have had it get stuck in nuetral. My shift linkage moves in a "U" pattern; low range is down and left, mid range is up, and high range is down and right. Somehow the linkage seperated, but still moved normally.

Can you hear a change in engine loading when you press and release the clutch?

 

[mmcdermott1]

No there is no change in engine. It is almost like it is in neutral but I have checked all linkage about a dozen times. There are two rocker arms that goes from the foot pedal linkage back to the hydrostat. One rocker arm comes into the top and goes clockwise and counter clockwise depending on direction of pedal. The other comes into the bottom of the hydrostat and goes the same direction regardless. These are moving when i move the pedal.
Mine is just a HI/Low gear and 2WD/4WD...i have tried all combinations and just wont move and engine doesn't even appear to think its in gear..no bog down no change in rpm..nothing.

 

[mmcdermott1]

One other bit of information. Although I cannot see the output shaft of the hydrostat, I can see the input shaft from the engine and that is turning just fine at the hydrostat input.

 

[coldkubota]

If your Fluid level is okay you might have clogged strainers. The B1750 is very much the same as the B1550 HST.
Do a search for 'B1550 Hydrostatic Trans whine' posted by alchemysa. There is a pretty good description of the problem and cleaning the strainers.
Hope it helps. Check the simple things as well like linkages.

 

[coldkubota]

One other bit of information. Although I cannot see the output shaft of the hydrostat, I can see the input shaft from the engine and that is turning just fine at the hydrostat input.

If you take the cover off your filter you should be able to look straight down and see the coupling between the propeller shaft and the input shaft on the transmission.
I'm just in the process of changing the clutch on by B1550 HST so I'm getting more familiar than I'd like with the shaft and linkages (service manual is helpful too and it covers the B1550 HST, B1750 HST and the 2150 HST)

 

[mmcdermott1]

Yes stainers were both cleaned thanks. In regards to pulling the filter cover off, are you referring to the hydraulic filter on top of the hydrostat, the one between your legs? I can see the input shaft, but I cant see the output shaft, that is all housed inside the casing. Actually I did just find a manual for the 1550/1750HST (shop manual) very good book to have. It hasn't helped diagnose my problem yet but it is good for showing how the thing is put together. I was told to take the cover off where the low/high shifter goes in. Was told that it sounds like it is in neutral...any thoughts on that?

 

[RobertN]

No there is no change in engine. It is almost like it is in neutral but I have checked all linkage about a dozen times. There are two rocker arms that goes from the foot pedal linkage back to the hydrostat. One rocker arm comes into the top and goes clockwise and counter clockwise depending on direction of pedal. The other comes into the bottom of the hydrostat and goes the same direction regardless. These are moving when i move the pedal.
Mine is just a HI/Low gear and 2WD/4WD...i have tried all combinations and just wont move and engine doesn't even appear to think its in gear..no bog down no change in rpm..nothing.

Mine is a different, older model. Two things have stopped my tractor... Once, a piece of brush wedged against the hydraulic disconnect for my loader and released the coupler. It effectively "dead-headed" the pump. The engine would bog and die.

the second was the range shift lever I mentioned above. All the hydraulics worked, but the tractor wouldn't move. It was stuck in nuetral, even though the handle would move like normal.

 

[alchemysa]

I think you said you checked it but make sure your heel hasnt knocked the turtle/hare lever into neutral.

Even though the wire mesh may be clean it could still be sucking air if the pipe from the trans to the HST is loose or broken. But I think you'd notice a nasty screeching (even worse than usual) if that was the case or your HST had imploded. My usual experience is that if everything sounds normal then its probably just a lever or linkage somewhere. (Frustrating, but usually cheap or free to fix fix when you find it.)

The turning input shaft and working PTOs means the clutch is OK so its either gotta be in neutral or the HST lever/pedals are not working.

Pushing the pedal should produce some sort of noise from the HST even if the tractor doesnt move. If youre getting absolutely no HST noise at all it may simply be a pedal/lever problem.

Be careful if its a HST pedal problem. If its in gear and you unexpectedly fix something it could take off.