How many trouble free Hours on your HST ??

[MossRoad]

I think the bobcat is a little different than a tractor HST. Same thing goes for my Power Trac. It really doesn't have an HST tranny. It has hydraulic pumps that turn hydraulic motors.

My IH had a pump inside the tranny that turned a motor inside the tranny that turned a gear box that had hi and lo range. That, in-turn, rotated the drive shaft that turned a differential in the rear as well as the PTO shaft.

While the variable volume pump is common to the tractor and the bobcat, that is about where the similarities end.

 

[RobertN]

It's a longevity issue that I'm worried about. that is, years and hours.. not just hours.. though the one post with 5k on it is a -good- sign. I wonder what differecne it would make if you spread that out over 20 ys.. etc...?

I.E. 5k hrs in 8ys.. vs 5k hrs in 20 ys.. etc.

I can't tell you about 5000 hours. But, my little Kubota has taken 20 years to get it's 1025 hours on it. From what I can gather, it sat outside it's first 400 hours. I have had it since '99. First year I had it, it was outside till I finished my tractor shed. When I bought it, it did have clean clear hydraulic fluid.

One of the things I look at is rentals... They get beat to death! A buddy bought a old rental B1700(or B7100?) with about 2000 hours on it. The frame was cracked in two, and had to be welded back together. But, the HST works great.

Does make you wonder though... My Farmall is 66 years old and still works great, although I only use it for parades etc. Wonder what condition my Kubota will be in in another 46 years

 

[john_bud]

It's a longevity issue that I'm worried about. that is, years and hours.. not just hours.. though the one post with 5k on it is a -good- sign. I wonder what differecne it would make if you spread that out over 20 ys.. etc...?

I.E. 5k hrs in 8ys.. vs 5k hrs in 20 ys.. etc.

Basically.. I am waiting to see if the tranny design proves to be as robust as the rest of the tractor.. or better.. etc. for instance.. on a geared tractor.. you can expect the engine to last a few thousand hours before rebuild. I know of many gear units that are on a 2nd rebuild.. but still have a stock tranny. Are the hydro units going to be this robust? I.E. in 50-60 ys whent he tractors are being restored are they going to be pretty much running clean.. except for a 3$ input shaft seal?.. like a typical surviving classic gear unit from the 50's is today... ??

Soundguy

Sound,

If you look closely at the guts of an HST you will find a piston pump and a piston motor. Same exact design as the piston pump your tractor uses for it's hydraulics. You concerned about it? We've both seen operable pumps with 40 years and 10,000 hours on them, no filter in the system and the fluid looking more like tar or a chocolate milkshake. Think how much better they would be with filters and regular fluid changes like an HST gets.

As far as that $3 shaft seal, best hope the 5 speed in your ford doesn't start popping out of gear! You may have to add a grand or more to that expense. Them puppies are getting up to the same range as the SOS repair cost.

Back to the main post....


I went by the local JD dealer the other day and decided to stop in. I asked the service guy how many HST's they have to repair in a year. He scratched his head for a bit and said not many...maybe one. I take that as a good sign.

jb

 

[slowrev]

I guess all those creeping hydros and reprogramming does not count as trouble ?

 

[Superduper]

I guess all those creeping hydros and reprogramming does not count as trouble ?

Ah hah! Here's where the subjectivity comes into play. Thus far, it doesn't looked like anyone mentioned anything about repairs of any kind. However, the original post, I was primarily interested in major trouble/repairs. How about if we categorized trouble as minor/major $500-/$500+ respectively? In my opinion, reprogramming doesn't count if it was for the purpose of fine tuning to match owner's preferences or needs, out of choice rather, than out of need.

 

[Soundguy]

I think if an HST were as easy to work on as a geared unit.. that might skew the results way more favorably too.

The more difficult something is to work on.. the more it may be avoided.

In the end.. it's a cost benefit thing. if the benefits outway the costs.. the choice is clear.

Believe me.. I'm not anti-HST... I just don't do very many tasks that would benefit from an hst.. thust I don't feel the need to spend another 1-2k$ on one. Plus.. I know I can slide gears and rails around if I have to.. I', not so sure I could tackle an HST rebuild though...

I think we will reach a certain point where materials technology will close the gaps in the race that may eventually obsolete the gear tranny.. and take away the possible loengevity 'bonus' that gear trannies have over the HST units..

I.E. better and longer lasting seal materials.. and better fluids and filters. Thus.. getting an HST that can run for 50ys and not leak all over the place. That would make it better in virtually all respects when compaired to a gear tranny...

Soundguy

The purpose of the poll was not to prove or disprove anything. I was just curious as to what other user's experiences have been. The questions were how many hours and whether there were any major problems. No subjectivity solicited here except I suppose what one would categorize as major. Frankly, I don't need the HST tranny to last forever, nor do I need it to last 50 years. If I can get good dependable trouble free service for 5000 hours before repairing, rebuilding, or replacing, I'll be happy. If it goes more, then I'm ecstatic. Might it cost more to maintain or rebuild or replace over 20 years, probably so. But what I'm seeing so far is very encouraging. What I was actually looking for in the responses was frequency of serious problems encountered and costs related to the hydros. So far no one has posted one yet. Since HST's are so prevalent now, perhaps greater emphasis will be given to rebuilding them when they get weak rather than junking them. Any system that relies on hydraulic fluid to work requires good pressure; getting weak with thin fluid suggests excessive pump or hydraulic motor clearances but surely that can be fixed so long as parts are available.

As for time tested durability, well I guess in 50 years when we do this poll again, we will know for sure. I for one will be dead by then so I guess I'll just have to take on faith what the data today suggests. So how about it guys, how many hours/years does your HST tranny got and how much trouble have they been? Let's get some more input so the data we collect is more meaningful.

 

[Soundguy]

We both know the most common issue of them popping out of gear are the detent balls and springs.

If it isn't that.. then we are talking about worn shifter/ forks..etc. I classify that amout of wear as damage. My post about 50 ys and a 3$ seal specifically disclaimed damaged units.. I.e... the average working trans.. ( either type)where it was just an age / hour issue.

Soundguy

Sound,


As far as that $3 shaft seal, best hope the 5 speed in your ford doesn't start popping out of gear! You may have to add a grand or more to that expense. Them puppies are getting up to the same range as the SOS repair cost.

Back to the main post....


I went by the local JD dealer the other day and decided to stop in. I asked the service guy how many HST's they have to repair in a year. He scratched his head for a bit and said not many...maybe one. I take that as a good sign.

jb

 

[755inNY]

JD 755. ~1300 hours in 16 years. No problems major or minor. Hydro fluid and filter changed every 250 -300 hours.

Jeff

 

[JimR]

My 1995 7275 27HP 4WD HST has 2600 hours on it. I bought it used almost three years ago. and it appears to have never been apart. I have had no problems so far with it. I do not baby this machine. It does get used for everything from hauling trees, moving dirt and rocks, grading, brush hogging and mowing fields.

 

[john_bud]

We both know the most common issue of them popping out of gear are the detent balls and springs.

If it isn't that.. then we are talking about worn shifter/ forks..etc. I classify that amout of wear as damage. My post about 50 ys and a 3$ seal specifically disclaimed damaged units.. I.e... the average working trans.. ( either type)where it was just an age / hour issue.

Soundguy

Exactly correct! Except on the 5 speed the "ball" is actually a hollow cylinder with a hemisphere on one end and called a plunger. Ford, always with the better ideas..... Bought a full set of plungers and springs about 2 years ago. It was $50ish. I didn't think that was too bad, especially given the improvement in shift feel SNAP! right in gear. You've probably seen my multiple posts telling people not to freak out and split a tractor until after changing them out.


I do think that you are selling yourself short. If you can do a gear trans, you can more easily do an HST. From reading your posts, you have skills.


On the question to the JD dealer - looking back, I think I used the work "rebuild" in talking to him - but used the word "repair" typing it. That may have caused confusion. {Sorry!!} Looks like I'm guilty again....still?

jb