L5740 surging forward and reverse

Joelogger

New member

Equipment
Kubota 5740, farmi winch, woods 8’ rear blade, Dettson 7’ blower
Jan 12, 2022
5
2
3
New Brunswick
Recently my l5740 HST had a slight surge when moving forward and reverse. Changed the fluid and filters, while doing this I noticed the rubber hose at the suction side of the hydraulic pump was cracked, replaced this. Now the surging is even worse and when I release the pedal quick it tries to go in the opposite direction. The linkage all connected to the pedal seem free moving. Looking for any advice to hopefully locate the problem before I have to look inside
 

Joelogger

New member

Equipment
Kubota 5740, farmi winch, woods 8’ rear blade, Dettson 7’ blower
Jan 12, 2022
5
2
3
New Brunswick
Thanks D2Cat, yes I have taken the mat out and cleaned the whole floor space ( wasn’t bad anyway), I got under and sprayed all the linkages with spray lubricant. I think it may have to head to the dealer.
 

lugbolt

Well-known member

Equipment
ZG127S-54
Oct 15, 2015
3,912
959
113
Mid, South, USA
make any difference if it's in high HST or low HST range? Have you tried to adjust the hst sensitivity if you have that adjustment in the dash?
 

200mph

Well-known member

Equipment
L4740-3 Cab, FEL, Fnt Snow Blower L2185, LP Finish Mower, LP Rotary Mower
Mar 3, 2017
1,200
35
48
PA
Curious if any progress has been made on the diagnostics or if problem solved.

The instrument panel can provide feedback on stored error codes, and view sensor outputs with engine off and running. This can be helpful in understanding if one of the sensors is acting up. Hold both switches down while turning key to on position. A beep should be heard. From there I believe menu H reports stored codes and A can display sensor outputs. One needs to be careful with this feature as you can mess things up. The WSM covers in detail the various menus.

Example:
1642724521017.png
 

rbargeron

Active member
Lifetime Member

Equipment
L5450, L48, L3250, L345 never enough attachments
Jul 6, 2015
966
84
28
western ma
I have no direct info, but the earlier version of the HST had an external damper on the linkage that limited the "speed" at which shifting actually took place inside. It compensated for abrupt pedal movements. To limit pressure spikes there must be a corresponding function inside the later design. The L5740 WSM should say something about it.
 

RichHuey

New member

Equipment
L4760
May 9, 2022
7
0
1
Phoenixville, PA
I have no direct info, but the earlier version of the HST had an external damper on the linkage that limited the "speed" at which shifting actually took place inside. It compensated for abrupt pedal movements. To limit pressure spikes there must be a corresponding function inside the later design. The L5740 WSM should say something about it.
My L4760 is having a similar problem.

Stopped being able to go forward all together, wants to go backward even at neutral pedal.
Surges when going backwards. Initial saw this problem after tractor heated up, now it happens all the time.

Anyone have any ideas?

Thanks

Rich
 

Joelogger

New member

Equipment
Kubota 5740, farmi winch, woods 8’ rear blade, Dettson 7’ blower
Jan 12, 2022
5
2
3
New Brunswick
My L4760 is having a similar problem.

Stopped being able to go forward all together, wants to go backward even at neutral pedal.
Surges when going backwards. Initial saw this problem after tractor heated up, now it happens all the time.

Anyone have any ideas?

Thanks

Rich
It ended up being the 2 proportioning valves, under the cab directly below the pedal. They were rusting within the coil end of the valve, and sticking real bad.
 
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rbargeron

Active member
Lifetime Member

Equipment
L5450, L48, L3250, L345 never enough attachments
Jul 6, 2015
966
84
28
western ma
It ended up being the 2 proportioning valves, under the cab directly below the pedal. They were rusting within the coil end of the valve, and sticking real bad.
Valuable post !! These machines are not very old and to have vital operational valves not be weatherproof is not typical of Kubota's historically high build quality. Hope they have revisited this component now that it is showing its vulnerability.
 

RichHuey

New member

Equipment
L4760
May 9, 2022
7
0
1
Phoenixville, PA
Thanks for taking the time to respond!

I need all the help I can get.

When you say proportioning valves, do you mean something like part # TD170-59310 ?

I replaced the lower one without any change. I will replace the top one next. (it is harder to get to...)

This failure is significant, with neutral pedal (even at start up) the tractor will aggressively go backwards, brakes don't do much. You have to think quickly and shut down the machine.

Let me know if I have the correct part #

Thanks

Rich
 

Joelogger

New member

Equipment
Kubota 5740, farmi winch, woods 8’ rear blade, Dettson 7’ blower
Jan 12, 2022
5
2
3
New Brunswick
Thanks for taking the time to respond!

I need all the help I can get.

When you say proportioning valves, do you mean something like part # TD170-59310 ?

I replaced the lower one without any change. I will replace the top one next. (it is harder to get to...)

This failure is significant, with neutral pedal (even at start up) the tractor will aggressively go backwards, brakes don't do much. You have to think quickly and shut down the machine.

Let me know if I have the correct part #

Thanks

Rich
I wil have to look at my boxes that they came in. I will take pics and post later
 

Joelogger

New member

Equipment
Kubota 5740, farmi winch, woods 8’ rear blade, Dettson 7’ blower
Jan 12, 2022
5
2
3
New Brunswick
I wil have to look at my boxes that they came in. I will take pics and post later
I have a couple pics to share, part#, and location of the proportioning valves is behind the guard beside the filter directly below hydrostatic pedal.
 

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