HST Power Loss on Kubota Grand L3940 HST+

[Rebel]

I haven't taken the time to read the entire thread so if this has already been discussed I digress,

Since you are concerned about the workings of the HST, I would suggest changing the filters and then cutting open the old filters to check for signs of component failure caught in the filter media.

 

[kuboman]

If you have tried this then disregard but what happens when you place range shifter in neutral and then press the hydro pedal forward and back. I believe if you have a problem in the tranny that sucks the power then it will do the same with the range in neutral. It should kill the engine. If not then you likely have a fuel delivery issue.

 

[dex3361]

You may have already checked it but is it possible that your brakes are dragging and robbing you of power. If my tractor has the brakes locked on it acts like it is low on power. I also agree that it could be a fuel flow issue. You could always take it to another dealer and have him check it out.

 

[D Texas]

Did you find the problem? If so, please share it.
I am having the same issue with my L3400.

 

[Rocksprings]

Did you find the problem? If so, please share it.
I am having the same issue with my L3400.

Check your messages Dallas.

 

[PhilY]

Have you checked any of the hydraulic safety relief valves? The reason I mention this is that you hydraulic fluid that flows the transmission is the same fluid going through the FEL and the 3ph. The 3ph is the last piece of the system that the fluid will flow through prior to returning to the trans. If a safety valve is kicking in prematurely, then you could be wasting fluid flow through the safety valve diminishing the flow for your HST drive. I would check your FEL operation basics. For example, if it stutters while picking up a load, you don' have enough fluid. If it feels spongy, then there is air in the lines, but it should have an auto bleeder. If if has a significant loss of power then, you either have a leak or a safety relief valve has failed and all the fluid is bypassing the system through it causing a large power loss in the tractor.

 

[mt180]

So rocksprings, what are these mysterious pm suggestions you're passing out? :laughing:

 

[Komanche]

Did you find the problem? If so, please share it.
I am having the same issue with my L3400.

Hi, I have the same issues on Bobcat 316 mini digger... (Kubota D722 engine)

 

[808]

hey rock springs is it possible to get that secret as I too have the same issue with my l3410
it would be greatly appreciated
thxs

 

[mtrusler]

Problem is main fuel pump I am pretty sure! Mine had same symptoms at 353 hrs, replaced pump and fixed. Mine is doing same thing again at 733 hrs. The must have problems with these small mechanical diaphragm pumps. Hope this helps. Rex

Hi,

I have 404 hours on my 3940HST and I am having the same problem as bowersautosales. Bleed the fuel system injectors and pump to no avail.
I have narrowed down the problem to the fuel lift pump part number 17121-52030. Does anyone have information or tips on how to locate the pump and replace this part?

Any help would be appreciated. First problem I have ever had with this great tractor.

Thanks.