HST or engine issue

[Mtsoxfan]

So I have my new tractor, but keeping the TC29D for other tasks. 1800 hours, I've been noticing a slow, steady decline in power from one or the other. Is there a way to determine, without special tools, which direction I need to start looking? I'd have to borrow tools like compression tester, as mine is made for gas engine. I do not have a fluid pressure tester either. For over a year, I've had no luck finding anyone willing to work on it without leaving for 6+ months. Really rural area.
Since acquiring used, I've changed the HST and hydraulic filters with OEM every 200 hours, and recently did a hydraulic fluid change. It may or may not have started after changing fluid. It is not OEM fluid, but met requirements. I use Power Service silver, injector cleaner and cetane boost on every tank. Hydraulic fluid full with no bubbles.
Going up my road with hills, I've always had no issue with running mid range. Now, I have to feather pedal, and eventually shift to low range.

Just looking for advise on a starting point. Thanks.

 

[ptsg]

Can you tell if the engine is bogging down when it starts losing power?

There is still a dry clutch between the engine and the transmission, used mainly to engage the PTO. Could be the culprit as well, so something to keep in mind.

 

[Mtsoxfan]

Can you tell if the engine is bogging down when it starts losing power?

There is still a dry clutch between the engine and the transmission, used mainly to engage the PTO. Could be the culprit as well, so something to keep in mind.

it does feel like it bogging down, or struggling..

 

[oldnslo]

If engine is losing RPM then HST is still doing its job. If tractor slows down but engine does not loose RPMs then it is clutch or HST or less common but happens a wheel is spinning inside the tire. This is normally noticed more at lower speeds and higher torque requirements

 

[Mtsoxfan]

If engine is losing RPM then HST is still doing its job. If tractor slows down but engine does not loose RPMs then it is clutch or HST or less common but happens a wheel is spinning inside the tire. This is normally noticed more at lower speeds and higher torque requirements

Thanks. It's bogging down. Loses RPM. And I did replace the fuel filter as well. I thought I bled air out, but after running a minute, it died. I bled system and it started up.

 

[ptsg]

What's the condition of the air filter as well? Might be worth taking a look.

 

[Mtsoxfan]

I took it out, it was lightly sooty. I blew it off with compressed air, and I could see light through it, but not like new. It might be time, I'll give it a shot.

 

[ericm979]

Does it have a lift pump? That may be getting weak. Though they usually fail entirely.

The shop manual may have a spec for fuel flow into the injection pump. If yours is below spec then that would narrow down the search space.

 

[Mtsoxfan]

Thanks. I checked the air filter with a vacuum cleaner, and it is not plugged, no change in vacuum when I applied. I'll see if fuel spec available.
I will continue reading through repair manual and see what else I can learn. Good thing its rain for a couple of days. Gives me some good dry project...

 

[IndyIan]

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

 

[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!