HST popping out of mid-range into neutral on downhill

[beowulf]

Well, I had to recalibrate the pucker factor a couple of times last week. So I am back at the trough looking for answers.

Twice, while going down hill very slowly with a load (boulders on pallet forks for wife's landscaping project) the tractor popped out of midrange and into neutral. AND because I was going downhill (estimate a 15-20% grade on a back road) the tractor took off - startled is too mild a word. I immediately hit the brakes and then figured out what had happened - i.e., it was now in neutral.

Later that day, now in low gear, but otherwise the same circumstances (downhill, very slow, with load), it popped into neutral.

I don't recall this ever happening before. The common factors: downhill, heavy load in front, traveling very slow and cautiously, everything else had been going well all day - a day of dislodging and transporting boulders.

Suggestions? Thanks for any attention you can provide this.

BTW: This has also caused me to rethink how I manage tasks in front of a running tractor.

 

[jonsstihl]

I'm not sure if it is actually popping out of gear but try the same hill again with the heaviest attachment you have on the back and in 4wd and I think you will find it goes much better. Brakes only work on the back wheels unless the 4wd is engaged and since you have a heavy load on the front tracton on the rear tires is limited.

 

[beowulf]

jonsstihl, Thank you for responding. I will check but think it was already in 4WD. The reason I say it popped out of midrange is that the actual lever was in the neutral position each time after the tractor sort of 'took off' on me on the downhill run. I had a box blade on the back during these incidents.

BTW, I have since resorted to backing down the hills in similar circumstances- i.e., heavy load on front.

 

[ericm979]

Was it fully in gear each time? Sometimes it's hard to tell. Is the detent functioning correctly?

 

[beowulf]

Was it fully in gear each time? Sometimes it's hard to tell. Is the detent functioning correctly?

Good point. My recollection is that I put it fully in gear each time but perhaps I did not. The way I was using the tractor most of time - as I recall - was to be in low as I used my pallet forks to get under a boulder, remained in low as I repositioned on the road, and then at some point would shift into mid range for the trip to the house. It seemed that it went to gear as usual - and sometimes, also as usual- I would have to re-engage and move a bit and then shift if it would not go in at the first instance. Later today or tomorrow I will pop the cover off the range shifter and keep it off for a while as I work. What is interesting is that it happened three times on one day - always down hill and always with a front end load.

Your explanation makes sense! Always look to the simplest explanation first. Thanks for posting. I am assuming by 'detent' you mean the catches that the lever engages when moving into different ranges.

 

[Henro]

Wow, that is a scary event!

Since your brakes worked to stop you it is unlikely the situation was caused by other than the gears popping into neutral I would think.

Not sure why backing down would make a difference, but perhaps someone can add something on that.

As indicated above, perhaps there is something preventing the linkage from going fully into the selected gear. But you would think this would affect the extremes and not mid range. Puzzling...

 

[beowulf]

Not sure why backing down would make a difference, but perhaps someone can add something on that.

Henro, it did not pop out when I was going in reverse down hill - that was just something I decided to do due to the very heavy load on the front. It just seemed safer given the load on the front and because it popped out when going forward downhill.

It does wake you up when you are proceeding very slowly and then all of a sudden you are going quite fast downhill.

 

[RjCorazza]

I had an L3410 for many years, and do not recall this happening. It HAS happened twice on my L4060 over the past 4 years.
It only occurred immediately after shifting ranges, and I believe that the range shift was only partially engaged. I now pay closer attention when changing ranges, and also move the machine hard after shifting.

 

[jonsstihl]

soory I missed the part where you mentioned the brakes worked to get you stopped. It does seem like a detent problem with the shifter

 

[Cougsfan]

I have had that happen a few times, and you are right, it can be quite scary. In my case it has usually happened right after I changed ranges and I did not engage the range selection lever all the way into it's detented slot. So when it has happened to me I'd put the blame on the driver, who is otherwise blameless