Hydro vs Gear Trans?

MattCole · May 11, 2001

I'm thinking about buying a JD 4200 or a 790. I'm concerned about the reliability of the hydrostatic transmissions, though, because I've been having problems with the hydro on my 16 HP Kubota and a friend of mine recently had to have the hydro transmission repaired on his JD (after some hard and heavy brushhogging) that cost quite a bit of money.

Are my fears of hydro transmissions unwarranted? Do the advantages far outweigh the possibilities?

I'd primarily be using the tractor for mowing and snowplowing.

Thanks!

Matt Cole

Mike_S · May 11, 2001

I am surprised that you have had problems with your hydro tranny. I have had two Kubotas and the 8200HST never had any hydro problems, or any other problems except for a broken tachometer cable--in the ten years I owned it. Your question will get similar responses to having an automatic or stick in a car--there are strongly opinionated people on both sides with my side leaning strongly toward hydros. I watch the small fleet of gear driven tractors cleaning off my school district's parking lots and sidewalks and watch the drivers stop, clutch, shift and go and then stop, clutch and go and realize how much quicker my hydro is at such chores and the same goes for FEL duties and mowing around my many trees and bushes too. I had one gear drive tractor (Yanmar) and am on my 5th hydro driven tractor (two Kubotas and three Deeres). IMHO, this is like cars, the early automatics were not very dependable (blew the auto tranny in my 57 Chevy five times), but today's automatics are very dependable as are the hydros. For ease of use when a lot of stopping, reversing, stopping and going forward is necessary, a hydro is difficult to beat. With that said, it is time to hear from the gear fans. Mike S.

cowboydoc · May 12, 2001

Matt,
I'll tell you what my experiences are personally and from talking to other people, mostly mechanics. As far as the ease of use on the hydro and time it will safe you it is a blessing!!! I have heard and seen the same issues as to reliability of the hydro. At the ranches back home we had tryed hydros when they first came out and they were not very good at all. They were constantly in the shop. Two years ago my uncle tryed another hydro and it just didn't hold up to the pounding that he gave it. Talking to JD mechanics and kubota mechanics the general consensus that I've gotten from them is that if you're going to use the tractor in light duty applications it will hold up just fine and perform like a champ. However if you are going to be using a machine in heavy use applications and pushing the limits of the tractor then it is not going to hold up like a gear driven tractor will. When I got my JD I talked to the guys in the shop and the salesman that I trusted. They told me for what I was going to be asking my tractor to do definitely go with the gear tractor and the power reverser. They said if I was hauling big round bales, pulling discs, plows, etc. that they didn't think the hydro would hold up. Kubota guy told me the same thing. He said if I went up into the M series tractor I would be ok but not to expect the hydro to perform on the L series for what I wanted to do with one. My whole purpose was getting a smaller tractor than my massey to move around easier so the M series was out.

I would love to have a hydro. I was out the other day digging fence posts and hauling dirt to fill them and thinking how nice one would be. I haul around 1600 round bales, pull a 12 foot disc, etc. with mine though and I know this will be debated by guys here, but from what everyone told me and personal experience I'm still not sold that they will hold up to the heavy duty like the gear tractors will. If you're going to just be using it for light duty work I don't think you'd have a problem and I'd definitely say go with the hydro.

doctordeere · May 12, 2001

Matt, in my experience as a JD tech, the reliability issue is about dead even between the hydro and gear trannys for warranty repairs. Beyond the warranty period, the gear seems to hold out beter. Main reason being that with a gear tranny if you get a bit of wear, it may be whining, but it'll still pull. On the hydro, wear causes fluid pressure loss and consequently a loss in tractive effort, and cannot be ignored.

Another thing to consider is tractive effort needed. A gear trans is 99.98% efficient (10 hp in, 9.998 hp out), where a hydro is only 40-60% efficient(10 hp in, 4-6 hp out). The power loss in a hydro is caused by both internal leakage and the conversion of energy into heat. Which brings up another point, heat. Hydro's will run hotter.

If you need maximum wheel hp, can you afford the loss with the hydro? Can you take the additional heat? Are you going to put high hours on the machine? All are valid points to consider when making the decision between hydro and gear.

"Doc"

GaryK · May 30, 2001

I HAVE A HYDRO ON A 4100 AND LOVE IT. I GOT IT MAINLY SO MY WIFE COULD USE IT WITHOUT FEAR OF DRIVING THRU THE GARAGE WALL. I USE IT TO PULL A BOX BLADE, FEL, TILLER, BUSH HOG AND MID MOUNT MOWER. DON'T HAVE MANY HOURS ON IT BUT SURE DO WORK IT WHEN I DO USE IT. SO FAR NO PROBLEMS

StoneHeartFarm · May 31, 2001

Doc,

I'm in the process of shopping for a compact. I need something to plow snow (and ground), mow the orchard and move some dirt with an FEL. The tip about older hydros helps alot since I may have to buy used depending on budget at the time.

I do have a few questions about the different trannys. I understand Hydro. But, I'm seeing Gear collar shift, syncro shuttle and power shuttle. Gear collar shift sounds like what I have in my car. Shuttle, I think is some kind of quick reverser. Power shuttle is quick reverse that you don't have to jam into place with your hand. Is that essentially correct? Of these three, which, in your opinion, is best? (I expect were talking FEL here, since I don't see how mowing or plowing would require a great amount of shifting). I haven't been on anything larger than a lawn mower in 25 years and that was an old farmall narrow front. I assume they still work about the same?

Also, on another thread, Bird (I think) mentioned a 2 stage clutch, and I don't remember anything like that on the old farmall. What is it and why do I need it?

SHF

PS. Guys, is this one of those cans of worms?

Bird · May 31, 2001

SHF, a two stage clutch is used on some geared tractors and is simply an arrangement to be used with the PTO. Pushing the clutch pedal part of the way down stops the tractor, but leaves the PTO turning, and pushing it the rest of the way down stops both (well, doesn't necessarily stop them, but disengages the power from them).

And I'll leave it to some more knowledgeable guys to tell you about the transmissions because there are several that I've never used. I've only used straight gears, hydros, powershift, and an Oliver with hydraulshift.

Bird

StoneHeartFarm · May 31, 2001

Bird,

Thanks. That answers 2 stage. I seem to dimly remember something like that, but its been a long time and there was a lot of different equipment laying around that I had to work with.

The problem in a nutshell, is I don't remember enough and things have changed enough that I'm afraid to start talking to the dealers. If I'm not educated enough to know what's right for me when I hit that lot, the dealers won't be able to help much. They'll be guessing too. So, with about 4 months to wait, I'm getting educated. (Gotta take a look at the Compact Tractor book).

SHF

Bird · May 31, 2001

Gotta take a look at the Compact Tractor book

Yep, Muhammad's book is well worth reading before you go talk to dealers.

Bird

doctordeere · May 31, 2001

SHF:

For FEL work, your best bet is the PowerReverser. One quick throw of a lever on the dash and off you go. It is, unfortunately, the most expensive of the gear drive transmissions. On the brighter side, I have not had to do a single internal repair on one yet.

The SyncShuttle is nothing more than a Collar Shift with synchronizers on the top shaft gear clusters (hence the name TSS - Top Shaft Syncrinized). Helps if you need to "shift on the fly" as opposed to standard collar shift where you must dang near stop the tractor to select a different gear.

Can of worms? Not really. Just different trannys for different applications. The real factor in your satisfaction is picking the right tranny the first go-round.

"Doc"

StoneHeartFarm · May 31, 2001

Doc,

Thanks for the tip. Any idea if all these transmissions are availble on all models (like optional car equipment?).

SHF

DDT · May 31, 2001

I have been a hrdo tranny owner, but learning too. when you swicth directions on a PowerReverser tranny is it smooth or very jerky?

dmccarty · Jun 5, 2001

DDT,

The PowerReverser tranny is very smooth when placed into reverse. The operator is supposed to wait until the tractor has stopped moving before changing to forward if moving backward or backward if moving forward. I still clutch out of habit before moving the lever to go forward/backward but its not required. I have found the PowerReverser very smooth if you do what JD tells you to do, wait for the tractor movement to stop and then change direction. Its very smooth. Far smoother than most of my gear changes in my truck. /w3tcompact/icons/smile.gif

Later...
Dan McCarty

cowboydoc · Jun 5, 2001

I agree with Dan the power reverser is very smooth. It's also nice because you have all the same reverse speeds as you do forward speeds with the power reverser. So I can set it fast or slow with the gearing. It works great.

raptor · Nov 21, 2001

Probably too late to get in on this, but what the heck. If you're going to use the tractor as a real tractor - only the gear tranny will do. For a lite weight wanna be tractor a hydro's the way to go. I can't abide a piece of equipment that sacrafices 15-30% inefficiency throuh the transmission. I know these a fighting words to alot of you all, but I ain't trying to get anyone's dander up - just stating my belief.
Stay safe

DocHeb · Nov 22, 2001

I think you're a little harsh on the HST in regards to ineffeciency. I know the most about NH Compacts, and in the example of the TC40, the PTO horsepower is 35 for the Gear and 33.2 for the HST. This is a drop of 12.8% for the Gear and a drop of 17% for the HST - not that great a difference between them.

Edited by DocHeb on 11/22/01 03:38 AM (server time).

gerard · Nov 22, 2001

Is the difference between drawbar HP a similar % difference? Seems like the hydro's would lose more power transferring power to the wheels than to the PTO shaft

cowboydoc · Nov 22, 2001

Gerard,
They do and that's why the small decrease in hp is somewhat misleading. I believe that's more where raptor was talking about. For serious farming he's right the hst just doesn't cut it. That's why you don't see an hst in the bigger utility tractors. While hst is a serious consideration for someone not farming it's not a consideration when you need precise mesh of ground and pto speeds. The hst is completely variable in this aspect whereas the gear tractor is constant.

gerard · Nov 22, 2001

That's kind of what I figured. Getting the "economy" model gear is sometimes regretted (mainly when doing loader work!) but that being the only tractor I've ever had I don't miss the hydro that much. One thing I would have liked had I known more before buying is a live PTO.

kerr · Nov 22, 2001

Thats not as big a drop or lose in power as I was thinkin .I realy like my H.S.T. mower and 4200 J.D.But for working hard day after day,I would want gears or a industrial strength automatic of somekind.Ol- Rapter dont beleive in power steerin or seat pads er nothin!Die hard old school tracterin!