Kubota wont go forward or reverse

[WLFrost]

I have a 2014 L4600 HST 4WD was going across the lawn stopped and then tried to go but it wouldn't move forward or in reverse but everything else works pto and the hydraulicswork like they should pulled HST filter and the oil is as clean as New but the pedal has no feel to it other than the springs any ideas what is the problem thanks

 

[North Idaho Wolfman]

See if the PTO spins when you try and move the tractor.
If it doesn't the clutch is out of it.

 

[WLFrost]

See if the PTO spins when you try and move the tractor.
If it doesn't the clutch is out of it.

Yes it still works the only thing I can come up with is internal linkage or a stuck valve hopefully! And everything else works fine thanks for your thoughts

 

[mikester]

Did you try changing gears from LO-MED-HI?

 

[Donystoy]

I would certainly suspect the pedal linkage especially if the pedal feel is different and your hydro shifter is not out of gear. Happened to me with my original b7200.

 

[WLFrost]

Yes tried all gears low medium and high and same thing . And I will look into the pedal linkage thanks and did they have to split your tractor to fix it thanks Wayne

 

[Donystoy]

Your tractor might have easier access to this location than the b7200 had.. Yes they wanted to split the tractor but I suggested they cut a small round hole in the side to facilitate the removal of the rod. They did this and welded the rod to repair it. Not sure what could be broken on yours but hopefully you can get some access to see the area. On the b7200 I could see the area after removing the top cover. I was able to get the tractor onto my trailer by using a long screwdriver.

 

[WLFrost]

Thanks going to have to split it because it's all cast thank you for your help I'll let you know how we make out

 

[rbargeron]

Thanks to ruger1980's post below I now know that model's HST is NOT controlled by solenoid valves - see below and posts #12 and #16

EDIT: Oops, the info I had posted on solenoid valves wrong - the L4600H uses a version of HST that still has a hydraulic regulator controlling Forward and Reverse, not solenoid valves. See the diagram in post #12 and component layout in post #16.

I didn't realize there was a redesigned version of the "side-by-side" HST for L-models that still used a mechanically linked hydraulic regulator for forward-reverse and speed control. The HST is combined into the the clutch housing. Part No. is TC404-59995.

The L4600H WSM should cover testing of charge pressure - should be somewhere around 300 psi (varies with rpm). Drive pressures are much higher - drive reliefs are set above 5000 psi.

Why it would just stop is a head scratcher - hope Kubota can offer some guidance. There have been several part numbers for this unit, now at the 4th or 5th iteration (started at TC404-59990).

 

[North Idaho Wolfman]

You don't have anywhere near the same linkage as a B7200.
All of your linkage is accessible without a split.
Also your linkage controls electronics, not mechanical input to the HST.

Yea what he said.. slow to type

 

[WLFrost]

Checked all the fuses that are in the fuse block and they where fine. That was one of the first things we checked unless there is some behind the panel and all the wires look fine maybe the solenoid valve is bad? We're going to get into it tomorrow with any luck we`'ll find out what's going on . And thanks for the info on my problem.

 

[ruger1980]

I would look under the floor boards at the pedal and transmission. Unless Kubota is not showing an updated model the L4600H HST appears to be mechanical linkage to a servo control valve. If so check the pedal attachment the rod ends on the linkage and the pinch bolt that secure the lever to the servo valve shaft. If all is OK externally then it could likely be in the servo valve which can still be repaired without splitting the tractor. You may need gauges to check charge and servo pressure to determine what the failure is. It could be just the feedback lever on the servo valve.

Of course this is assuming your L4600 is manual control. If electro/servo, diagnosis will be different.

 

[WLFrost]

Thanks we did a pressure test and had almost nothing for pressure but was mentioned that if the valve was stuck there probably wouldn`t be any pressure .
Thanks we`'ll look into it this afternoon. All info is welcome

 

[ruger1980]

It depends on what pressure you were checking. You have to check the charge pressure first then check the forward and reverse servo pressures and then forward and reverse drive pressures.

 

[WLFrost]

Ok thanks

 

[rbargeron]

My post #9 was wrong - it's revised now that I realize its a whole different HST design than I thought. Sorry for the misdirection play.

Here's the HST's component layout from the parts website for the L4600H tractor. There's a pipe (part 060 in the diagram on the right that delivers charge pump oil to the regulator. If it got kinked or crushed by debris under the tractor it could starve the regulator and the tractor might not go either way.

 

[rbargeron]

In addition to no F and R motion, if the pto does NOT work turning a load, the clutch is the most likely root cause. Low or no pressure from the charge pump directly points to a bad clutch. An L48 owner in NJ (with similar HST) lost F and R motion a few months ago and found a new clutch was needed. Splitting the machine is necessary, but a new clutch costs far less than an HST.

Dick B.

 

[North Idaho Wolfman]

I would make 100% sure that the PTO will turn with power not just free spin, and that when you engage the HST it does not stop spinning.
Easiest way to do this is power a ground engaging PTO powered implement.
The PTO will free spin but when put under a load it stops dead.

I know these models of HST are known for ripping the splines out of the clutch disk.

Also if the HST main shaft is not spinning you will not get feed back to the HST pedal and you will not get any pressures.

 

[WLFrost]

Thanks they worked on it last night they couldn't find any problem with the pump I'm thinking it maybe a internal problem

I would make 100% sure that the PTO will turn with power not just free spin, and that when you engage the HST it does not stop spinning.
Easiest way to do this is power a ground engaging PTO powered implement.
The PTO will free spin but when put under a load it stops dead.

I know these models of HST are known for ripping the splines out of the clutch disk.

Also if the HST main shaft is not spinning you will not get feed back to the HST pedal and you will not get any pressures.

Thanks for your reply I'll talk to them about what you mentioned thanks

 

[WLFrost]

Well thanks for the info from all that was willing to give some split the tractor went though everything and came up with nothing put it all back together same thing talked to a couple of dealers and they said it doesn't happen often but you will have to put a new HST unit in to fix it so hear we go and found out they have up dated this unit 4 times since it has come out! Nice you think they would know what's going wrong with it. But thanks for all you in put Wayne