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...