Kubota L3560 HST lacks pushing power and top speed.

[treeguy2145]

My Kubuta L3560 Hydrostatic lacks pushing power when trying to fill the bucket. When I hit the dirt pile I get a ton of whine and the engine doesn't bog down at all, in fact, the RPM increases slightly, as you may notice in the video. Stall guard is OFF. Seems to be better after running the tractor for 30 minutes or so. I'm not sure how to share a video on this forum, so I uploaded it to YouTube: https://youtube.com/shorts/yc9bxEc_rTw

Similarly, the top speed should be ~16mph according to the manual but I only achieve 10 on flat ground

Engine runs well, the bucket seems to function perfectly and the 3-pt works perfectly as well. I did notice a bit of a buzzing sound, which you can hear in the beginning of the video.

What could cause this? Is my hydrostatic pump/motor bad? Could it be a charge pump issue? Are my relief valves malfunctioning?

 

[North Idaho Wolfman]

Sound to me like you have stripped splines on the hub or the input shaft on the HST.

Further test would need to be performed to be sure of that.
Do you have a PTO powered Implement?

 

[BBFarmer]

Assuming you've owned this tractor for quite some time and are just now experiencing this issue?

I know when I push into big thicker piles mine usually lacks the power to pick up a big bite. Mine's got the smallest of the loader options, the LA555. I will generally back up a take a smaller bite out of mounds.

The 3560 can definitely be an under powered tractor given its size in certain situations.

Especially the cab models, A/C on and what not. Heck I'll usually bog as I cut my rows while lifting the loader over bushes as I swing around. Typically why I cut with my loader off.

Take the wolfman's advice here and follow his diagnostic strategies, feller's knowledge is invaluable!

 

[treeguy2145]

Thanks for the reply! I actually got this from an auction. It has 400 hrs on it and I just replaced all the fluids and filters when I got it last month. The problem existed before and after the fluid change. The price was good, the engine runs well, and it works fine as a log skidding tractor (as I intend to use it) but it bothers me that it seems to be lacking some pushing power. The real thing that confuses me is the engine when pushing. Instead of bogging down, it actually increases RPM when I first push into a pile (even with auto throttle advance off)

 

[treeguy2145]

Hey, thanks for the reply, Wolfman. I do have an implement on the back. It is a skidding winch that I just got a few weeks ago. The PTO seems to work just fine. I can pull large trees with ease. If I pull a very large tree while at a low idle, I am able to stall the engine, so there seems to be a good transfer of power to the PTO at least.

What tests would help to confirm if the splines are the problem?

Again, I appreciate your help. I have a lot of experience with ATVs, cars, mowers, and other gas-powered equipment, but this is my first hydrostatic tractor

 

[North Idaho Wolfman]

What fluid and filters did you use?

 

[treeguy2145]

The oil filter, air filters, fuel filters were in this kit: https://www.amazon.com/dp/B0CBSHL62G?ref=ppx_pop_mob_ap_share

I didn't use the hydraulic filter from that kit. Instead, bought one from a dealership. Probably could have used the kit one but I wanted to be safe.

The second hydraulic filter was https://www.amazon.com/dp/B0CBPS29XN?ref=ppx_pop_mob_ap_share

Oil was some diesel 10w30 I believe

The trans/hydraulic fluid was Triax Agra Utto XL, a Super UDT equivalent https://a.co/d/iMNd86X
11.1 gal added in accordance with the manual

I should mention the fluid replacement did help a bit. Before that, the fluid seemed a bit low and symptoms were worse

 

[rancher1524]

What gear are you in when you hit the pile of dirt.

 

[North Idaho Wolfman]

Well here my 2 cents
#1 I think it's a big mistake to use aftermarket filters and fluids for the HST, which you did.
#2 Is does not say that the fluid is SUDT2 compatible or comparable.
It says UDT and UDT2 (10 years obsolete fluid), and those are much different than SUDT2.

Now, is this issue or not I can't tell you, but it has been know for both incompatible fluid and incompatible filters to cause the exact issues that you're experiencing.

 

[PaulL]

He did note he had the issue both before and after. But no knowing what fluids and filters it had when he bought it.

If it was the splines, wouldn't it just not go at all, rather than being down power? I mean, I can imagine a friction fit still working, but if the splines are damaged enough for it to spin, then surely it'd just spin under any load at all?

 

[treeguy2145]

Fair point. Perhaps I will try Kubota Super UDT2 in this machine. The manual does state that regular UDT is also permitted in this machine, but who knows, maybe that could play a role in the performance and issues I am having. Thanks for the suggestion

 

[TheOldHokie]

Fair point. Perhaps I will try Kubota Super UDT2 in this machine. The manual does state that regular UDT is also permitted in this machine, but who knows, maybe that could play a role in the performance and issues I am having. Thanks for the suggestion

View attachment 162209

Brand of transmission oil is not going to change that behavior

Dan