Does anyone have knowledge converting a manual transmission forestry d7h to powershift if I acquired a parts machine? It has all protection guards, cab, a/c. Could this even be done or is there too much difference. Seems the manufacturing of the frame and final drives would be the same but I don't have any facts about it, maybe the transmission is integrated into frame design.
Is there any particular reason for doing this?
I can't imagine running a kg blade with a manual transmission.
I wasn’t aware the D7H was available in manual gearbox? I remember seeing a pic of a D8L SA once that was gearbox rather than a transmission
I think it was originally a government forestry machine. I'm not a fan, almost didn't buy it but it came with too many attachments to not to
Wow,a rare find then. Do you have any pics of the beast please? Thanks
Wow,it’s a fair beast of a thing.Looks well. In the UK,those early D7H LGP’s were a rare thing to see.My first experience with was on a road job in the middle of winter when the topsoil was soft going. We had various Cat 631C’ and D8H and 463’s struggling to get over the high soil tips.This new Cat D7H lgp stole the show easily shoving the 631’s up the tip. Great machines
It seems like there was a direct-drive version of the D7H immediately the model was introduced to replace the D7G but then it disappeared before the D7H was eventually phased out. I wonder if Cat thought that because there had always been a good market for a DD D7G automatically meant there would be similar for a DD D7H but a subsequent lack of sales proved them wrong.
You would have to replace a lot of parts, a fair bit of the operators station would be different from the dash to the transmission controls. Even stuff you might not think of like the transmission cooling system would most likely be different. I would have thought it would be worth more a a direct drive machine.
If ever a machine that's a keeper it would be this one as is.
Hum, maybe this man has a unicorn.... When CAT came with the Modular concept, The H series till the D7 size, they also developed a modular DD system, this being said lets see the differences...at least in D4 and 5´s thats how it goes. Clutch is wet type with 3 frictions and actuation is Hydraulic, it has a charge pump same as the Powershift, as the Gearbox comes with FWD/RWD Power Shutle. Only the 6 gears are mechanical. The charge pump is responsible to flow oil through system to cool and lubricate, to provide press for shutle module, and clutch module. Clutch is not really a conventional clutch where the press plate is released to load the FW , its a modulator that modules pressure to the clutch Pack. The side of driving is no diff from a PS, except for gear change and T/off. The power shift alow gear changes under load and this system does not, as it has to be clutched to manually make a gear change. Basically once operator chooses the working gear , 3rd for instance, shutle lever is neutral, just pull the shutle lever to FWD and it modulates T/off. of course at the enf of the row , to reverse one either pull lever to RWD or use the pedal modulator to stop. I woudn´t mind to have one like this. At all. Pls post a picture of controls to see if its like the 4´s and 5´s.
I've read of d6/7h models with dd. First one I've heard of in the wild. Probably to change it you best pick up the radiator cap and roll another one under.
I wish it was a shuttle. I have an allis chalmers 655 that has a shuttle that I like. This Machine you couldn't even get into forward or reverse until wornout clutch brake was fixed. It would just grind gears. It seems just like a semi. I wish I could make it a power shuttle. Otherwise something is broke on it. Sounds like I need to get into the manual
That machine has a dry clutch?
I believe it runs in oil, quite a heavy thing although the winch gave a zx200 a run for the money removing it
A distant relative of mine boiught a new D7H direct drive back in the day. I only ever saw if from the outside. He also bought anther direct driver D7H, but it was a grey import from Japan a LPG model converted back to conventional width grousers. I can only assume a lot of LGP dozers in the asian region were direct drive.
Well , one keeps on learning... TC and PS machines are not very eficient fuelwise... but they are fool proof. At least in my region when JD came with the "powerquad" TXM, half powershift and half manual, nothing matched it, i can't figure out why dozers does not have something alike.... Today machines with lock up converters do the trick but are much more unreliable. Anyway if have a D7H PS shouldn't be impossible to convert one or the other.... not taking account the assle it is.
It just sucks going from forward to reverse because if the machine isn't dead stopped, it will just grind gears or eating clutch brake trying to help stop machine
That's the difference between operators and drivers.
Fuel is cheap compared to operators and getting the job done. All that heat the TC makes and has to be removed from the system, that is all burnt diesel making that heat. I saw a late model power shift 7F and a direct drive 7G doing chaining work and the 7G with 20 more hp would chew through 2/3rds the fuel the 7F would go through. But when it comes to pushing dirt and anything needing quick forward/reverse the PS wins hands down. The absolute best would theoretically be electric drive because electric motors are so efficient and they have full torque at 0 rpm.
The d7e is the machine you speak of. I wander how they ever worked out
Could be if RG LeTourneau was still around. Sadly he ain't and no one has picked the mantle.
You would need a donner machine there is so many parts you would have to change out. you might have to change flywheel housing , flywheel, add torque convertor, oil cooler, all lines and piping, transmission, all controls, maybe steering clutch control, hydraulic pump, drive shaft, maybe radiator. that would be a major undertaking and cost prohibitive with out a donner machine
This............
Young man, for those of us that grew up with direct drive, usually we can shift forward to reverse faster than a power shift. As the left hand moves to disengage the master clutch the foot goes down on the brake and on the old models the right hand is already moving the forward reverse "johnson bar". The instant the shift is made the master is engaged and of course the brake released. I have hundreds and hundreds of hours on a D7 with a splitter on the blade corner. Every hour direct drive.
Although on a long day doing dozer work, you will be noticeably more tired than if you are running a powershift
56, the world has changed. All the old iron took both hands, both feet, all day.
And a darn sight fitter, so much so going to gym after work wasn't a thing then.
This one is for sale here at the moment. I actually saw it in the flesh at Farmfest a month ago. Was completely rebuilt from a burnt out wreck to as new standard, with comparable price tag. https://www.constructionsales.com.au/items/details/1987-caterpillar-d7h/OAG-AD-23374649/
Alright I will be the one to look silly........what is the third pedal for? I remember some old tractors that had a pedal for blade tilt, but I have never seen one in that new of tractor. It can't be for use with the clutches like the older tractors. I have never been in an H that wasn't diff steer, and that was a 6 lgp.
Wow that thing looks very low hours, at least the C frame and rake does. I've dabbled a few times with manual trans dozers, it would take some getting used to, and I don't think it would be fast enough for me when shifting and such. And power shift is so handy when you use 2 dozers at once, any guesses how and why you need to do so, other than having no one around to help you?
That would be the master clutch, fwd/reverse behind the steering clutch levers and gear stick in front of the seat.
With a foot clutch, foot brake and decelerator, be a handful to operate on anything other then flat ground if you wanted to start off at anything but full rpm. Machine needs to at a dead stop to change direction/speed. So invariably you are going to have a foot on the clutch, the other on the brake and the engine running flat out. At least with the hand clutch you can use the decelerator, if they were fitted.
That would be difficult, I suppose you would just need to hand throttle it if that is what it needed at the time. I'd really like to spend some time on that machine and see how well or not it works. What would make them easier to deal with would be a clutch type for and back shuttle, so you wouldn't need to full stop for a direction change.
You don't need to decelerate the engine on a direct drive when changing direction or speed, just WOT all day.
I know you do not need to, but it saves wear on the clutch.
The older dd dozers of all colours never had any decelerator and worked just fine for many thousands of hours.
I’ve seen pictures of a DD 6H’s cab. It was the same except it didn’t have a decelerator. Just a foot clutch and a brake
I'm trying to remember the direct drive dozers that I have run; 3T,17A, 9U, 2U, and a 19A. The 19A D9 was fun. I was pushing DW 20s. As I recall it had 6 gears, and once you got the hang of it you could rattle up behind a scraper and go from 6th to 2nd right before you hit the stinger and pick them up smoothly..........as long as they didn't bury the can and stop! Anyway, all of those tractors had tall levers coming out of the flour for the clutch.
Oil clutches really made a difference, easier on the Machine & Operator & would last 1000’s of hrs looked after properly. I remember going with my Dad during summer break, building logging roads in the Coast Mountains of BC with a 14A D8 the sound I will never forget, full throttle forward & then reverse with just a little change in the governor. Wished I had a camera
At times I do the powershifts the same way, not all day though.
I have a mate with a DD D5H LGP, iIRC it doesn’t have a de-accelerator. I still feel bad changing gears or direction at WoT no matter what it is in. The first dozer I purchased (and still have) was a Fiat BT7C 70CI and it has a five speed stick shift gearbox with a powershift forward/reverse. As far as I can tell the best of both worlds. Fast direction changes and direct drive fuel efficiency. Torque converters are a wonderful thing though when you start knocking over large trees ect. Takes all of the shock loading out of coming into contact with objects that don’t want to move!! For the machine and the operator.
For those who are Familiar with PowerQuads from JD, i wouldn´t mind to have a Dozer with such a system, 1-Multi-disk master cluctch in oil, 2-Power Shutle, FWD / REW 3-Manual 6 speed Sinc trans 4-Half Speed module in the Power Shutle, just for the sake of reverse. This just cause fuel is 1.50€ liter where i am... it would worth the extra labour in it. My D5H goes about 100ltr day and the guy next door with a D41 DD does it with 60/70 in a 6cyl engine...
Cat makes the D6XE which is an electric drive machine. Previously Cat also had the D7E in the early to mid 2010s Also Cat makes some other machines with electric drive now, like the 988XE, some of the haul trucks, etc
Are the D6XE’s any good? Or any of the Cat electric drive stuff for that matter? When I saw the D7E was released I thought it could be the next big leap forward in development and if they got it right could soon replace mechanical transmissions, but I don’t think they were very popular in Australia. I have only seen one in person I think and it was in a machinery dealer yard a few months ago. I might be wrong about the popularity here but I haven’t seen them about, so I am very curious what people thought of them. If they are starting to expand the range I am thinking it must have been successful?? Electric drive seems like a pretty neat idea… would hate for it to short out though, from memory the voltage and current in the D7E was pretty impressive IIRC!
I have a friend who is now in management of a large contractor in Ohio. His company had several D7Es and said that both the company and the operators really liked them. I don't know if I've ever seen one in the west though.
Was the 9U a dry clutch? I seem to remember something about them that one had to watch.
I read somewhere that from engeneering point of view it made no sense to fit diesel electric system in something below 1k HP. But that was some 20ya when i was studying master mechanics. At the time it had to do with having a diesel engine, a altrnator and driving units(AC motors), manufacture this units in industrial grade and add ons to perform was not considered worth wise from cost perspective. This days maybe i make sense ... with bateries and stuff.
Wabco had 250 ton diesel electric trucks at the Mt Hagan mine New Guinea in the late 60's being loaded by diesel electric wheel loaders. Cat bagged the **** out of them but Cat had only just built a 100 ton truck. This explains how far advanced LeTourneau/Wabco was. Some time ago I had a yarn with a bloke from Komatsu who didn't have any idea of the lineage of Letourneau equipment until I explained It. He did his own research and was gobsmacked, couldn't understand why Komatsu hasn't picked up the ball and run with it