Traction My Tractor Slips Going Down Hill While Mowing

[Henro]

I am very very confident it is a traction issue not internal slippage. I have a gravel covered clay base hill to my upper meadow . Roughly 100ft of 20 percent grade . I have 3 hydrostatic vehicles that go up and down this hill. A Kubota Bx2660 tractor that I only go up and down in 4 wd and turtle gear or else a wheel will slide. And it will feel like a runaway. The same thing with my Kubota Xc1100 UTV ...same engine similar tranny and hydrostatic. In 2wd one wheel will slide and speed increases without slowdown by hydrostatic . So must do in low 4wd ...no slide and hydrostatic keeps me slow. Again No brakes needed. My 3rd hydrostatic vehicle is a husqvarna lawn tractor 15hp 2wd only. I no longer use it on that hill. Because a year ago coming down that hill the one rear tire lost traction ( I saw skid mark after the fact) hydrostatic could not keep it held back and I rolled it after jumping off .( It still runs by the way). Lesson learned all 4 wheels need traction for hydrostatic not to be overcome .

Same here. But do not agree that this is only a HST tractor issue.

I have a B2910 which is exactly the same tractor as the OP, but with a couple more HP. 18 Years ago I learned to be sure to be in 4WD on slopes. Could not believe how damp grass acted like ice. Actually everything here is a slope so I use 4WD 99 percent of the time. About 1800 hours on the tractor now. By the way, my BX2200 acts exactly the same too.

The OP should be happy his assessment of what is going on is likely incorrect. Otherwise it would cost big bucks for repairs.

I am firmly in the camp that what the OP is experiencing is normal. Every once in a while I get a repeat of that action when I accidentally bump the 4WD lever into the 2WD position and do not notice. .

 

[k0ua]

Same here. But do not agree that this is only a HST tractor issue.

I have a B2910 which is exactly the same tractor as the OP, but with a couple more HP. 18 Years ago I learned to be sure to be in 4WD on slopes. Could not believe how damp grass acted like ice. Actually everything here is a slope so I use 4WD 99 percent of the time. About 1800 hours on the tractor now. By the way, my BX2200 acts exactly the same too.

The OP should be happy his assessment of what is going on is likely incorrect. Otherwise it would cost big bucks for repairs.

I am firmly in the camp that what the OP is experiencing is normal. Every once in a while I get a repeat of that action when I accidentally bump the 4WD lever into the 2WD position and do not notice. .

Yes, my first "wild ride" was in a Kubota B7500 with gear transmission. It doesn't matter whether it is gear or hydro, when the rears break traction and you are in 2wd, that is all she wrote, and you are going down hill and picking up speed. Drop the bucket, drop something you have on the 3pt to drag the ground if you have it, or just ride it out to the bottom. Because pressing on the brakes sure ain't gonna help. That alone tells you there isn't anything "broke" inside the transmission or gear train, but the brakes are on each rear axle, and have NOTHING to do with the gear train. Pressing on the brakes WILL NOT stop your slide. If anything it can make it worse by making sure traction is never regained. You can regain traction by speeding up by if hydro pressing the forward pedal or gear by flooring the accelerator pedal. But unless the traction conditions on the slope changes it may not do any good to speed up to regain traction.

 

[Industrial Toys]

At least, if you made the mistake of going down a hill in 2WD, you should have good steering and control on the front wheels. I think I did that a time or two on my JD 770.

 

[ptsg]

At least, if you made the mistake of going down a hill in 2WD, you should have good steering and control on the front wheels. I think I did that a time or two on my JD 770.

The mistake is not exactly going down hill in 2WD. The mistake is not having weight in the back of the tractor where it should be. This is often over looked and people tend to forget that the loaders will also take weight of the rear wheels.

Back in the day where 2WD tractors where far more common, people couldn't going down a hill in 4WD, because they didn't have it. So they had to put weight in the back, to get the traction needed.

 

[JWR]

It's not slipping internally. One or both rear tires is/are slipping.

This is why things are as they should be when in FWD.

SDT

Yep. Pretty obviously true. The OP just hasn't seen or been able to tell that the rears are slipping or one of them has stopped turning, etc. In case he is still in denial , I think I feel a wager coming on....

 

[4570Man]

What do your brakes do? If it’s sliding like it probably is they’re useless. If it’s truly slipping internally the brakes should stop it.

 

[jonsstihl]

Reminds me of the time I went down an intermediate ski slope with a unimog on wet grass. We were setting up snow cannons getting ready for the fall/winter snowmaking season and I had a couple stands in the back second gear 4wd drive engaged and started down the slope. I had just started driving this unimog a couple times so wasn't super familiar with it but as soon as the slope got fairly steep I could have sworn it popped out of gear and was freewheeling so I did the first thing I thought of. pushed in the clutch and pumped the brakes and tried to keep her headed straight down. was quite a ride. ended up bouncing around and sideways on the flat part at the bottom. the two stands I had in the back ended up on the ground but I managed to keep it shiny side up.

in hind sight I should have just floored the gas and left the clutch out I would probably have regained traction. learnt that lesson later that winter driving snow cats. when the snow pile you are on lets go avalanche style you put the sticks all the way forward and try to keep it straight. you eventually outrun the "avalanche" and regain control, then you go back up and do it again cuz the trails got to get groomed.

 

[Diggin It]

Shall we recap?

Have Observer check for tire/wheel rotation
Check for evidence of skid/slide in turf (ie torn grass)
Try DiffLock (Engage before slippage begins)
Try brakes
Try with more rear weight


Anything else?

 

[jonsstihl]

sounds like a complete check list to get to the bottom of the issue.

 

[JWR]

Reminds me of the time I went down an intermediate ski slope with a unimog on wet grass. We were setting up snow cannons getting ready for the fall/winter snowmaking season and I had a couple stands in the back second gear 4wd drive engaged and started down the slope. I had just started driving this unimog a couple times so wasn't super familiar with it but as soon as the slope got fairly steep I could have sworn it popped out of gear and was freewheeling so I did the first thing I thought of. pushed in the clutch and pumped the brakes and tried to keep her headed straight down. was quite a ride. ended up bouncing around and sideways on the flat part at the bottom. the two stands I had in the back ended up on the ground but I managed to keep it shiny side up.

in hind sight I should have just floored the gas and left the clutch out I would probably have regained traction. learnt that lesson later that winter driving snow cats. when the snow pile you are on lets go avalanche style you put the sticks all the way forward and try to keep it straight. you eventually outrun the "avalanche" and regain control, then you go back up and do it again cuz the trails got to get groomed.

Great commentary -- which ski area are you grooming ? I usually ski in Quebec every year BUT the border stoppage with Covid-19 put a temporary stop to that...

 

[jonsstihl]

this was in bromont first pitch of the cowansville/montreal ski trail right at the top of the mountain. this was back in 2004 though. the mountain has changed alot since then.

 

[Industrial Toys]

So did Bill look at his hill for obvious skid marks?

 

[JWR]

this was in bromont first pitch of the cowansville/montreal ski trail right at the top of the mountain. this was back in 2004 though. the mountain has changed alot since then.

A Ha! Some of that side does get steep. I have not skied Bromont since around 2004. Recent seasons have been terrible in the Townships. I've been going to Tremblant or more often to Mt. St. Anne. Two or three good ones near St. Anne too.

 

[ruffdog]

So did Bill look at his hill for obvious skid marks?

Depending on the hill, skid marks are left in another location too.

 

[wotalota]

I operate BX24 on a hill in 2WD cutting grass etc. without problem. I have experienced a runaway a few times. Going down hill using the higher gear, medium speed it will switch into neutral. In my case it has only happened with a leaf bagger attached so I have associated it with that weight imparting a pushing effect. By the time you realize what is happening the speed pick up makes it difficult to make a sideways turn to regain control. I still cut grass in 2WD, high gear but take it slow going down hill just in case it happens and use 4WD low gear with the bagger.

 

[Diggin It]

By the time you realize what is happening the speed pick up makes it difficult to make a sideways turn to regain control.

You most definitely do NOT want to do that. Once you're freewheeling, keep as straight a line as possible unless you need to avoid something like a tree or creek.

 

[Industrial Toys]

Why I don't like to see people who aren't cool, calm and in control, running equipment when things go south. I have watched hundreds of plan crash videos and am always impressed how calm pilots are just prior to dying. In fact, I don't recall even one, freaking out. At least not outwardly.

 

[jonsstihl]

that would have been right around the time I was grooming trails on the weekend shift. We groomed them during the day with escorts around the machines and at night also so if there was ice it was never there for very long. twice as much grooming as any other hill that just grooms at night.

 

[JWR]

that would have been right around the time I was grooming trails on the weekend shift. We groomed them during the day with escorts around the machines and at night also so if there was ice it was never there for very long. twice as much grooming as any other hill that just grooms at night.

I can remember in the old days many ski areas groomed during ski hours. Now I think the lawyers have control and won't allow it. I was always fascinated with you guys on snow cats grooming impossible places. I've seen a few where the groomer was lowered down by cable (or held back by one anyway.) I wonder if there is a forum on snow grooming ? I don't want to derail this thread any more than I can get away with !

 

[bill18163]

Both rear tires are about 13 lbs. I should mention that I don't try to cut grass on my hilly areas in 2WD on purpose. I don't use 4WD on my flat areas because it tears up the grass sometimes when turning. Then if I forget to put it in 4WD on the hills I get in trouble.