HST Power Loss on Kubota Grand L3940 HST+

[TripleR]

My dealer is similar to that described by rScotty, we are in the midwest where winter and summer temps are not as extreme as many locations and they don't stock anything but UDT, or didn't as of last year when I bought some. They will order it, but don't see the advantage over regular UDT or other good quality fluid. They have been in business for over fifty years and sell NH as well as Kubota.

I'm not advocating one way or the other.

 

[doelake]

Hello Guys... Remaining Frustrated as I'm back with no real progress to report on this issue IMO...
After taking my L3940 to the dealer yet again and asking them to check the HST+ specifically, they reported the HP reading at the PTO is right where it should be and that the HST+ trans seemed "normal" to them. I ask if they could check the pressures in the HST+ as I wanted to be sure that there wasn't damage or defect in the trans pump, etc... they didn't indicate anything was wrong and simply said that I had the settings on the HST+ out of whack and shouldn't use the HST+ features when tilling, etc. Not acceptable, IMO...

Recently during spring planting season, we tried to use this 3940 with a 6' tiller... it cuts deeply into the hard, clay soil great with no rpm loss when standing still..., but as soon as you begin to creep forward in LOW/LOW(turtle), the rpm's die and you must lift the 3pt. to a very shallow depth inching slowly to keep it from loading the engine and dying as you move forward... I know that this machine had MUCH more power under load and motion when it was newer... it only has ~ 440 hours on it now. No general fuel, filter or engine performance issues/dealer maintained.

For a better background as to what may be the issue: I hired a son(21) of a friend as a "helper" two years ago and showed him the ropes working with me during that spring/summer.... he did ok under supervision working with me. The following year, I got him started and then checked in with him weekly(I'm 6 hrs. away) as he worked on the farm to plow, till and plant corn, beans, clover, etc. in fields and food plots and then dress the woods roads, etc.
I've since fired him after discovering many lies including not working hours as claimed and waiting until just before I got there to rip around trying to get everything done/mowed from weeks of doing nothing. I found that all of my implements used with this tractor were bent, broken and abused... he was turning with this tractor and implements still in the ground and I suspect that he severely overloaded the trans in too high a gear/range during that season of abuse.

If I can ask of someone here...
What components should be checked/repaired/replaced in the Hydraulics or HST+ that would have been damaged by this type of abuse and cause this power loss during forward/back movement?

I'm actually to the point where I'm going to trade this machine in on a L5240 or a used L in higher HP to be able to do the work I need to...
Is it reasonable to expect that an L3940 should be able to handle a 6' rototiller in the clay soils of SE Ohio??

Thanks so much for your help on this perplexing problem... I love my Kubotas and don't fault the machine although this is getting very frustrating. This is my last shot before getting rid of it and going to something in the 50 HP range... I appreciate anyone's suggestions.
Thanks, Rob

Hey Rob, read the posts on your thread. I own a M59 TLB purchased new in 2010, that summer I was working on site when I noticed an instant power loss when depressing the foot throttle/HST pedal..... I keep my "auto trottle" switch on always...... I couldn't get the tractor to move or operate at more than an idle crawl, and I wondered what damage I had done to create such a problem.......
I climbed underneath the chassis and followed the cables from the foot pedal, and there is where I discovered the cable had caught on the chassis, rubbed the sheathing off and kinked the line, rendering the tractor dead in the water..... I was able to straighten the kink, and drive the tractor back home, I had the dealership pick up the tractor and change out the trottle cable assembly.....problem solved and has never returned!!!
I can say the dealership was perplexed, and had never seen anything like that in the past, sometimes they look for bigger problems......

Good Luck,

Anthony

 

[mmorisoli]

I switched to SUDT2 on my L3940 at 400 hours and love the improvements. Lower gear noise in high gear, less whine, better responsiveness with all the controls. Personally I feel it is well worth the added cost. My $0.02 worth.

 

[Rockin' G Ranch]

I just noticed the same thing. Got my L4740 back yesterday after having all the fluids and filters changed by my dealer. I was working on the ranch and said to myself "...the controls to FEL, 3 point and rear remotes seem to be responding much smoother." There is also absolutely no whine from the HST.
After reading this thread I check my receipt and sure enough the dealer used Super UDT2 fluid.
I plan to call him tomorrow and let him know how much better the tractor responds with that fluid.

 

[Bluegill2]

I'll run SUDT2 in mind and don't have HST.

 

[s219]

So what is the factory fill on an L3200 -- are they still using regular UDT from the factory?

 

[MessickFarmEqu]

So what is the factory fill on an L3200 -- are they still using regular UDT from the factory?

no, its SUDT from the factory.

 

[rbargeron]

This thread is an example of what happens when there is a long hiatus with no further discussion of the original poster's subject. After a couple curious references to PM's by others, the original poster stopped posting 1-1/2 years ago, without reaching a conclusion about what was causing the loss of power when engaging the HST. The thread has now shifted over to a conversation about UDT vs SUDT.

Unusual whining noises that change with temperature or fluid type are symptoms of fluid film performance and are almost always secondary, not the root cause of a power-reducing malfunction. HST noise is usually not from a condition that significantly increases the load on the engine. In fact, if an HST were to fail internally, it would most likely go into neutral and stay there, not capable of loading the engine at all. The original poster had said the tractor coasted easily on inclines. With an HST that's a convincing indicator that the major parts of drive train are fine. If an engine is bogging-down without being over-fueled (black smoke), the culprit is more likely in the cruise control, fuel delivery system or the governor. As always, prompt cheerful refund if the opinion stated is bogus. Dick B

 

[crazyal]

I can get my 4240 to hit a point where the engine just dies but I really have to push it. My driveway is pretty steep and since I start at the top and head down there's little work for the engine to do to move the tractor. Coming back up is different. If the snow is deep and I try going up in M with the H-DS set to high I can get the engine RPMs to go from about 2500 to 1500. It really seams like a wall, for example the difference could be as little as .25 mph. I've always assumed that it's the stall guard. Without it on the engine drop is much more gradual, it starts sooner and more predictable. With it on it seams like it counters the operator pushing the HST beyond the power the engine has. I usually don't have the Auto H-DS on since I didn't like the feel of the computer shifting up and down when I was right at the point where it wanted to shift. I just like control.

For those who are having this issue have you done any tests to see if there's a difference with Stall Guard on and off?

 

[wmonroe]

I've never really used the stall guard on mine but next time I have it out I'll give it a try and see what difference it makes. My driveway is rather steep too, never gauged the incline but it's steep.