Jumping HST on B26

[gotcha]

I'm trying to locate something in my Workshop Manual for the B26 for the HST as I feel I have a small problem with it. When I'm driving (forward/reverse) at a constant speed it will jump and go faster. Not a tremendous increase of speed, but enough if I were backing up to an attachment and someone was there to assist me and it jumped someone really could get hurt. (Pedal has not been moved by the operator)This condition happens when at idle or with it say at 1500 or any RPM's . Any ideas as to what may be happening?
The Gotcha Man

 

[easygo]

If the pedal is down even a little in HI range I have heard of the same lurch and in fact my much smaller tractor does the same thing. It happens more when engine is not up to operating temp. My dealer claims that in High Range most HST Kubotas do that. I can't say I tried them all to give an independent confirmation of that.

 

[gotcha]

If the pedal is down even a little in HI range I have heard of the same lurch and in fact my much smaller tractor does the same thing. It happens more when engine is not up to operating temp. My dealer claims that in High Range most HST Kubotas do that. I can't say I tried them all to give an independent confirmation of that.

easygo, Any where near Waldoboro on the coast

Thanks for your comments. My problem does it in all speeds, High, Mid and Low. Temp is up to operating temp. or at least should be as the unit has been running for better than an hour when I have it happen. Come on back with some more suggestions please.
The Gotcha Man

 

[easygo]

Gotcha Man,

I have no farther knowledge on the problem, I'm surprised that someone much more knowledgeable haven't made a remark. Fortunately for me I have no other experience with transmission related issues. I'm near Bangor but Waldoboro is certainly a nicer town. Easygo

 

[dfkrug]

Gothcha, my B21 is very jumpy in HI range also. I just finished
completely rebuliding the HST, rear end, and both of its gear
boxes. It may be very similar to the B26. This jumpiness may
be better when the oil is warmer.....I have not tested that.

 

[gotcha]

Gotcha Man,

I'm near Bangor but Waldoboro is certainly a nicer town. Easygo

Only because of Moody's Diner. The best and friendliest diner in the USA. You can see I'm kinda bragging.
The Gotcha Man

 

[gotcha]

Gothcha, my B21 is very jumpy in HI range also. I just finished
completely rebuliding the HST, rear end, and both of its gear
boxes. It may be very similar to the B26. This jumpiness may
be better when the oil is warmer.....I have not tested that.

Thanks for your input. My son told me that he has not had the problem after he has been using BH for awhile but did notice it when he first started to run it. I guess he is kinda answering my question for me. I had mentioned it to him before, but said he never heard me. That's the way kids are. They only hear what they want to I guess even at 38. The Gotcha Man

 

[gotcha]

Gothcha, my B21 is very jumpy in HI range also. I just finished
completely rebuliding the HST, rear end, and both of its gear
boxes. It may be very similar to the B26. This jumpiness may
be better when the oil is warmer.....I have not tested that.

Thanks for your input. My son told me that he has not had the problem after he has been using BH for awhile but did notice it when he first started to run it. I guess he is kinda answering my question for me. I had mentioned it to him before, but said he never heard me. That's the way kids are. They only hear what they want to I guess even at 38.
The Gotcha Man