Kubota L6060 stutters/shutters when moving and raising implement

[aherring]

Hello,

I am a new Kubota owner - picked up a L6060 in Feb 2014. I have a dealer installed FEL, FEL 3rd function remote, and rear remote. I am use to a gear/clutch tractor, so this HST tractor is a bit new to me.

My problem is that while driving the L6060, it will shutter as I raise or lower an implement. It won't do this every time, and some times are worse than others.

My thought: It is as if the hydro pressure feed to the hydrostat drive is linked to the pressure feed of the 3-pt lift, and when you hit a bump with a load held by the 3-pt, it creates a pressure ripple that then causes the tractor HST drive to hiccup as it drives (slight back/forth jerk). That hiccup then causes the implement to bounce again, and that causes the tractor motion to hiccup again, and on and on, until it stabilizes. This does not happen when implement is not present or when it is on the ground (ie, mower).

I've tried all the settings for implement lowering speed (ie, knob under seat) - no help.

Any suggestions or ideas? I may need to return it to dealer to check out.

Thanks!
Alex.

 

[TripleR]

I would talk to the dealer, I had an L5030 and now L5740 and never experienced what you are describing and my cutter and box scraper are about 1100 pounds. I transport on rough dirt and rock roads as well as the highway between farms.

 

[aherring]

Thanks - yes, I think I will end up taking it to the dealer. On the phone, they had no idea and have not heard of this before. We'll see.

 

[C4Ranch]

What gear were you in?
What rpm?
What are you doin when it happens?
Can you consistently recreate it?
Have you checked all fluid levels?

 

[aherring]

Any gear will do this (all 3 ranges)
Any rpm will do this but usually I am<1200 rpms when it's the worst.
As mentioned above - accelerating forward or backward while raising/lowering 3-pt will cause it to happen
I can reproduce 75% of the time I try it and I've checked all fluid levels (tractor has 50 hrs on it -practically new)

Thanks!

 

[C4Ranch]

Strange. I've heard loose lug nuts can do this. Other than that I'd get it to the dealer stat

 

[MHarryE]

Is there any chance you are bouncing in the seat and it momentarily cuts the engine when your weight comes off the seat?

Have you tried the different propel modes? I am not sure how a 60 series varies from my L5740 but if similar, try without auto-throttle - in fact cut it down to plain Jane controls to see if you have the same problems.

 

[rbargeron]

.... It is as if the hydro pressure feed to the hydrostat drive is linked to the pressure feed of the 3-pt lift......

Welcome to TBN, Alex. Other than the fluid reservoir there is no connection between the two systems. Each system has its own pump. Engine speed will affect both pumps, but the pumps don't affect each other. It sounds like the 3-point hitch is "hunting" enough to make the engine hunt too. Dealer should be able to adjust the 3-point. As always, prompt cheerful refund if info is bogus. Good luck, Dick B

 

[Retired Iron Peddler]

To me it sounds like hydraulic cavitation. Running the engine too slow to replace the hydraulic fluid in the cylinders when lowering the attachment, particularly the loader, which causes air to enter the system. Since air is compressible, it makes the hydraulics "stutter" and jerk.

Bill

 

[aherring]

Problem update...
The tractor has been at the dealer for about 3 weeks now. I had to make 2 trips back to demonstrate the problem to various people there. We have narrowed it down a bit. The 3-pt lift does not lower the implement smoothly (that is, it is not a problem in the hydrostatic drive as we originally thought it might be). The problem can be demonstrated with a heavier implement on the lift, such as a mower. As you try to lower it slowly using the lift control lever, at first a small shutter begins and that grows to a very large shutter as you continue to lower the implement. It is definitely some sort of feedback thing. The mechanics in Sanford, NC, do not know what it is, and the Kubota service rep from Winston Salem, NC, does not know what it is either. I've asked the dealer to try this out with another L6060HST and hope they will do so soon. I can't imagine some other tractor owners would not have already complained about this if it was a general design fault. I will keep this post updated as I find out more. Thanks.