HST or engine issue

[Mtsoxfan]

Check the governor? Probably mechanical I assume, It may not be reacted enough to decreasing rpms?

I just read that in the troubleshooting section for tractor. There is an internal and external spring. I'll check the external anyway tomorrow. Further reading on subject tonight. Thanks.

 

[terrtay]

I have a Kubota 3400 HST that was bought from a private person. When I got it from the guy the power steering was almost nonexistent he said to rev the engine and it will steer. I drove the tractor home and started checking it out and found a pencil size hole in the hyd pump suction hose, after replacing the hose the steering was much better. However due to the air entrapped in the hyd fluid there was some damage to the hydrostatic drive system. The wear causes leakage and power loss in the hyd system which is slowly getting worse, causing the engine to work harder and use more fuel to move the tractor. The only time I can put the transmission in high range is on a paved surface with it in 2 wheel drive, or the engine won't come up to max RPM due to the load and loss from leakage within the transmission. So basically what I am saying is it could be the engine loosing power but it is probably due to transmission wear.

 

[dieselscout80]

If you have eliminated the easy maintenance things like filters etc then start with other things.

Try decreasing the amount you have pressed your hydro pedal down as you go up the hill which increases power but decreases speed.

Questions:

Does your fuel filter remain full when it is bogging down? If not you may have the line from tank to fuel filter restricted.

Have your injectors been tested they are a wear item.

Have your engine valves been adjusted?

 

[SATOHBULL]

S. It may or may not have started after changing fluid. It is not OEM fluid, but met requirements.

I'm always suspicious of fluids. If there is any doubt in your mind, I'd recommend changing again with a known good brand. That's assuming you used a house brand rather than one branded by a oil company.

Not as cheap as some other things, but cheaper than most and won't hurt anything. Save the fluid you take out for reuse if it doesn't fix the issue.

Edit to add: Much smaller machine, weightwise, but my JD455 garden tractor acts much different when using farm store fluid that meets spec vs JD fluid. But works best with full synthetic 5w50 which was recommended by the tranaxle maker in a phone conversation.

 

[Mtsoxfan]

While replacing the air filter yesterday, I discovered a mouse nest in inlet. Because the inlet is flat for 3/4 of it, it was able to withstand the suction of a diesel engine. I can go up hills in 2nd gear again. Thanks for all the support.

 

[dieselscout80]

Thanks for posting your finds and fix!