Puny HST Drive Power

[KnuckleDragger]

While returning from the field to the barn following mowing, my L5740 had a sudden loss of drive power. The tractor was working fine. I had idled for a moment to talk to my son. As I was resuming, the pedal kind of went to mush and I lost about 80% of forward power. I stopped, did a cursory check at roadside, but didn't notice anything out of the ordinary. I didn't want to leave the tractor on the county road, so I crept back to the barn at a whopping top speed of 3mph. I had to get washed up for an Independence Day-Eve celebration, so I haven't done any further troubleshooting.

The tractor is new (<50 hrs), under warranty, and I have dealership service scheduled next week to install rear remotes. I'll let them to the T&E and repair, but I am curious if I have abused it or what may me be the problem.

Thanks,
Chris

 

[TripleR]

Well with 50 hours, you shouldn't have been able to tear it up if you tried.

I have a 5030, so I will be interested in what you find.

 

[leonz]

While returning from the field to the barn following mowing, my L5740 had a sudden loss of drive power. The tractor was working fine. I had idled for a moment to talk to my son. As I was resuming, the pedal kind of went to mush and I lost about 80% of forward power. I stopped, did a cursory check at roadside, but didn't notice anything out of the ordinary. I didn't want to leave the tractor on the county road, so I crept back to the barn at a whopping top speed of 3mph. I had to get washed up for an Independence Day-Eve celebration, so I haven't done any further troubleshooting.

The tractor is new (<50 hrs), under warranty, and I have dealership service scheduled next week to install rear remotes. I'll let them to the T&E and repair, but I am curious if I have abused it or what may me be the problem.

Thanks,
Chris

some things come to mind;

A. transmission linkage/oil spool with foot pedal

B. forward reverse pilot valve in transmission controlled by foot pedal clogged or stuck wide open with oil bypassing in relief with debris/broken spring.

c. clooged oil filter screen or cartridge filter affecting oil delivery.


d. turbine in torque converter


e bad or bypassing charge pump-the symptoms fit

 

[Egon]

A fifty cent pin dropped out!:thumbsup:

 

[KnuckleDragger]

All those causes sound plausible to me. The 50 cent pin would be my luck. I learned a $60 lesson this week to do a better job on my pre-op walk-around check when a missing bold holding in the back pin of the right 3pt hitch allowed the pin to drop in the field and cause a bracket to mangle and shear.

 

[KnuckleDragger]

SOLVED!

The problem, as it turned out, was the knucklehead in the driver's seat. My 5740 has an auto-throttle advance that couples the throttle to the HST pedal. When I stopped, I must have disengaged it with my knee. The funny thing is, I swear that lever didn't even exist until I had this problem!

Chalk this one up to the "ingorance-that-naturally-occurs-when-machines-do-the-thinking-for-us" category. Looks like I need another visit to the operator's portion of the manual.

 

[TripleR]

SOLVED!

The problem, as it turned out, was the knucklehead in the driver's seat. My 5740 has an auto-throttle advance that couples the throttle to the HST pedal. When I stopped, I must have disengaged it with my knee. The funny thing is, I swear that lever didn't even exist until I had this problem!

Chalk this one up to the "ignorance-that-naturally-occurs-when-machines-do-the-thinking-for-us" category. Looks like I need another visit to the operator's portion of the manual.

Glad to hear it was something simple.

I understand to a point the good things about the improved HST on the L40 Series, but I am just not sure it is a vast improvement over the L30 Series or others. I was going to get one, but bought a used L30 instead.

 

[JOHNTHOMAS]

Bought my 11th Kubota last month. A F3080. It wouldn't pull the steepest parts of my yard. Oops, had it in high gear. In low or turtle it will climb the side of a barn. Raised mowing deck and it wouldn't go back down. In the back of my mind I was thinking another mowing deck on one of my tractors had done that. Well, called dealer and Gary the parts man told me to trun the hydraulic speed adjustment knob. Did that and it raises and lowers perfect. When I read your post I was willing to bet it was a simple wrong handle, knob, switch or some thing simple. Glad that's all it was.

 

[dfkrug]

My 5740 has an auto-throttle advance that couples the throttle to the HST pedal.

I got a chance to do seat time in the L5740HST+, and I thought it to
be very impressive. It's an incremental, though ergonomic improvement
over the earlier, more conventional Kubota HSTs.

Even the "auto throttle" is a very helpful addition, IMO, especially when
you do a lot of loader or forklift work. I am on-and-off the seat, and
constantly adjusting the engine speed on my main tractor, so I see
its advantage.