HST Just Won't Stop, Quit, Woah!

PineRidge · Dec 23, 2003

Re: HST Just Won\'t Stop, Quit, Woah!

 What would or could you break ?
Do you think something would or could be damaged internally ?



Old Hickory I don't think that this is a problem of damaging the tractor HST as much as it could be a problem of running into something else with a run-away tractor. /forums/images/graemlins/shocked.gif

Mrwurm · Dec 23, 2003

Re: HST Just Won\'t Stop, Quit, Woah!

Mike, from what I understand about hydrostatic transmissions, what you described is normal and inherent in the design. Lubing your control points and is always good and will help, but the real issue here is the design of the trans. Most, older style hydros actually incur an increasing load to the foot pedal actuaters as the load increases on the tranny. As far as I know, all NH's use this 'older' technology. Some examples of tractors that do not use this type of system are the John Deere ehydro's and the Kubota Grand L's. These tractors, according to their ads, will slow down regardless of load. Some of the Kubota product literature does a good job of explaining how they improved on this old hydro technology. They (Kubota) claim they have solved this problem.

My NH TC30 has the 'old school' hydro, which is why I like the treadle style hydro controls. I rock my foot backward when I want to stop. I never rely on the pedal to return on its own.

Disclaimer:
I am not a mechanic. I learned this from reading product brochures and talking to dealers.

Old_Hickory · Dec 23, 2003

Re: HST Just Won\'t Stop, Quit, Woah!

Thank you
PineRidge. /forums/images/graemlins/cool.gif

art · Dec 23, 2003

Re: HST Just Won\'t Stop, Quit, Woah!

Just seeing this post again has tweaked my mind a little and I think I'm going to have to get into the service bullitins a little.

PineRidge · Dec 23, 2003

Re: HST Just Won\'t Stop, Quit, Woah!

Jim you appear to be the man! This morning I put white lithium grease on the HST cam roller. I then adjusted the return spring to the max position and took the TC-40D out for a test drive on the hills.

Now when my foot comes off the forward pedal the tractor stops immediately, there is no hesitation whatsoever. It stops so apruptly in range two that you had better be prepared for it. /forums/images/graemlins/shocked.gif I also notice that once stopped the tractor will start to roll backwards when it is pointed up a hill. This never happened before which leads me to believe that the HST was never returing 100% to the neutral detent. I just assumed before that the HST was acting as its own brake in the neutral position and thus holding my on an incline without the use of the brake. Now neutral means use the brake, thats why its there. /forums/images/graemlins/grin.gif

Thanks for your input regarding this problem, you have put my problem to rest.

Merry Christmas All!

Egon · Dec 23, 2003

Re: HST Just Won\'t Stop, Quit, Woah!

Good show. Sure wish my problem was that easy to rectify.

Egon

jinman · Dec 23, 2003

Re: HST Just Won\'t Stop, Quit, Woah!

Mike, you might find that you don't need the spring adjusted to its maximum tension. New Holland actually has a measured spring length dimension that is supposed to represent the ideal tension. The spring tension is supposed to provide the best balance between bringing the transmission to an abrupt neutral position and taking too long (testing your pucker response). If I take the time to clean the roller path and relube it every 25 hours, I don't need that much spring tension. If/when the pedal starts to become sticky, I just get out my can of spray lube and do an application. So far I haven't needed the spring readjusted, but then I am in balmy Texas weather as TC35Dforme pointed out. In colder climates, you will probably need more tension. But be careful, I've disengaged my cruise control a couple of times without my foot on the forward pedal and stress tested my seat belt as the tractor came to an immediate halt. /forums/images/graemlins/shocked.gif /forums/images/graemlins/blush.gif I know what it must feel like to be a calf roper and have that horse suddenly stop. If I hadn't had my seatbelt on, I'd probably been riding the hood. /forums/images/graemlins/grin.gif Just be careful the first time you disengage cruise. Keep your foot on the pedal. /forums/images/graemlins/smile.gif

PineRidge · Dec 23, 2003

Re: HST Just Won\'t Stop, Quit, Woah!

Jim thanks for the tip on the cruise, unfortunately the week I got the TC-40D home I had it in range 2 with the cruise set and made the mistake of tapping the brake without my other foot on the HST pedal. I was thrilled that I had my seat belt on, but I think it left a mark in my midsection because the stop was so quick. My foot is now always on the HST pedal before my other foot even touches the brake pedal.

Looking at my spring tensioner it was within two complete revolutions on the locking nut of being at maximum stretch before I touched it. So I opted for the 2 full turns tighter. I am happy with it, if I feel that it is a bit too responsive then I'll split the difference and back the locking nut off one full revolution. It has been cold here and temperature may indeed be a contributing factor as well.

It's really great to be able to get almost instant answers to problems that arise by using this TBN site.

Thanks Again,
Merry Christmas To All

yellowsocks93 · Dec 23, 2003

Re: HST Just Won\'t Stop, Quit, Woah!

The transmission could break I suppose. I would think something internally could be damaged just as you are not suppose to go from forward to reverse real fast in an automatic car. Like shifting into forward while still backing up. Why would you try to stop your tractor that way when you could just shut the thing off if it gets out of control? How many of you shift ranges on the fly when they are not synchronized?

jinman · Dec 24, 2003

Re: HST Just Won\'t Stop, Quit, Woah!

( Why would you try to stop your tractor that way when you could just shut the thing off.... )

Yellowsocks93, you are way, way off base here in your assumptions as to how a hydrostatic transmission works and also what is best to do if the forward pedal sticks. Please consider this a learning opportunity. The hydrostatic tranny is nothing like an automobile transmission. Rather than go into a long description and comparison, I'm just going to say that the hydrostatic transmission only works when there is fluid flow and you only get fluid flow when the engine is running and the hydraulic pump is supplying fluid. If you shut that engine off, you will put more stress on the transmission than suddenly reversing directions. This will make a hydraulic motor try to become a pump. You will shock the transmission much more than if you just step on the pedal for the opposite direction.

I can see how you might think suddenly reversing directions on a tractor would not be good if you make a comparison to and automotive transmission. It's hard to accept that the hydrostatic transmission in our tractors is designed for quickly changing directions. It's one of the reasons hydros are so popular. /forums/images/graemlins/grin.gif I'm also guessing that you have a gear transmission on your JD. Quick forward to reverse gear shifts on a gear transmission are not good unless you have a shuttle transmission. Even with shuttle shift, the tractor will slow before reversing directions.

If you have specific questions, just ask. There are a lot of folks here who will be more than happy to give you answers without "talking down" to you. We were all young once and most of us learned from watching/asking an experienced person, or through trial and error. Take my word for this too, trial and error on an expensive tractor is not something I would recommend. Happy Holidays!