Bulldozers with hydro transmissions.

[CountryBoy]

Recieved my copy of Equipment World Magazine.They have an article on 85 to 130 Horse power dozers. 7 different dozers listed and 6 out of 7 of the dozers have hydro transmissions.


Case 850 LGP and 1150K.Hydro is a new feature here.
Caterpillar D5G (Caterpillar 3046 six-cylinder Diesel)
Deere 650 LPG and 700 LPG (Full Feature hydrostatic drive)(Power Tech turbo diesel)
Komatsu D37PX-21 D39PX-21 and D41P-6 (Komstat hydrostatic-drive transmission)
Liebherr PR 712 B-M Hydrostatic - drive powertrain(Liebherr D 924 T-E diesel engine.
New Holland DC-100-LPG Dual -Path,hydrostatic-drive transmission(Cummins Diesel)

Dressta TD-9H DD LPG,TD-9H LPG Extra & TD-12C LPG FULL Power 3 speed transmission.

This article covers operating tips of the dozer it does not advocate or not advocate Hydro's.

 

[gordon]

</font><font color="blue" class="small">( 7 different dozers listed and 6 out of 7 of the dozers have hydro transmissions.
)</font>

They had to leave one for the gear heads. /forums/images/graemlins/tongue.gif

</font><font color="blue" class="small">( This article covers operating tips of the dozer it does not advocate or not advocate Hydro's. )</font>

Sounds like six to one in favor of the hst anyway. LOL

But on the serious side of the coin alot of heavy equipment is going to hydro. It's progress simple as that. Guess that the heavy equipment makers have figured out how to get rid of the heat and deal with the minimal hp loss.

I wonder how tuff they really are?

Gordon

 

[ScottAR]

Hydrostatic makes a lot of sense on the small machines as they are mostly used on smaller jobs where manuverability is more important than outright push. Much past 130hp, your gonna see powershift/power dividers almost exclusively as they deliver more power to the ground.

One reason Dressta is powershift instead of Hydrostatic is that Dressta still uses the Dresser designs which was originally IH back in the day. They are produced somewhere in Eastern Europe. Komatsu owns Dressta.

 

[Taylortractornut]

John Deere burnt me on the 750 and 850 Hydrostatic. All the ones ive run new and used wanted to pull left or right too much and every 8 months on the 750 and once on the 850 JD got 7500 out of redoing drive motors. I love it in a track loader and on crane and excavator chassis. The one thing that got me was i tried a new Cub Cadet, and a new New Nolland and both were hst and they boh sang when traveling.
I think on the Cat its a hydraulic drive transmission and you use the double epicyclic planetary gears to counter rotate the tracks. The thing i hated about the 750 deere was it weighd more had 40 more HP than the D5B gear drive and the D5B could out work it badly. The 850 could out produce the D5 till it got hot. The 850 caught fire and the operator didnt know a line had ruptured under the cab. when it got worm in the cab it had meled the cutoff switch and it just ran till itself cremated. I ran a newer 750 the other day and it was much inmproved but im still a gear drive man. I got to run a new D5C and its low track hydrostaic and it has a cruise controld that compensates a bit for speed loss. I dont want to sound like im knocking Deere too hard, they are good machines but they never have held in there with the old D5.

 

[Hambone]

We have a JD850 and a 550. Both seem to be good machines. The 850 is a 1996 approaching 7000 hours and is run in one of the worse environments.
We have had it track bad twice, and both times a sensor fixed the problem.
The pumps are Saur-sundstrand and can be service lots cheaper through them.
We did loose a final drive, but, don't know if they are different than the gear models or not.

 

[ScottAR]

Cat uses a power divider and powershift. The high drives have differential steering. The power from the trans runs through a differential to both sprockets. There's a hydraulic motor mounted to a spider gear in said differential. Going straight, it's locked out. When the motor turns, the tracks react respectively up to and including counterotation. Steering is controlled by a lever that looks like a outboard motor tiller. Clear as mud?

This goes for all the high drives up to the D8R. D9R and up use clutches still, although they are computer controlled now too. I'm not caught up on the big boys.

Oh yeah, a power divider is a torque convertor that has a planetary reduction built in for a "boost."

 

[CountryBoy]

Man,
You guys are creating some very good insight on the operations/mechanics of these big boys.........I like it............ /forums/images/graemlins/smile.gif

 

[Taylortractornut]

I have a customer that has a logging company and they bought 2 850's a few years ago. One is a great mchine and one is destined to drive them broke. I have a few good experiences on a 750, just the olderones didnt have a cruise control and that gave me a bad impression when theyd loose torque and speed on good ground. The gear drive 450 550 and 690 are some of the sweetest machines around.

 

[jtn]

I will put the John Deere 700H up against anything on the above list. That is one helluva tractor. As for the 750 and 850 I think the new generation (C series II) is a lot better.

You said you ran a new D5C, did you mean D5G? The G series and the JD H series both use electronic controlled hst transmissions as does the Komatsu D39. That is the way all the small tractors seem to be going.

I prefer powershift/torque convertor but the 700H makes friends real fast.

JT

 

[Taylortractornut]

Your right it was a D5G, i passed the machine this morning on the way to work. Im a little familiar with the 700 Deere. My local dealer brought us the sheet before it came into production. Im uncomfortable without a power shift machine lol. I ran a friends grey market D5 high drive and it is a sraight shift 5 speed. Its awkwards to drive at first especially trying to hand throttle and ease up to a scraper to push load. The older 750 i used to use was a pain trying to ease up on a pan some times it had spot in it when you eased back on the shifter it would stall before, then when i added power to get it to move it would jump and bump the pan a bit hard then i had to make a run from a pi$$ed off Terex operator lol.