D7 3T VS D6 9U

Dozer Newby 2021 · Mar 25, 2021

Hi, dozer newby here, learning about older units and I have the opportunity to buy either a D7 3T or a D6 9U for the same price ( $7200 ) . Our use is cleaning up raw land, 40 acres that has old roads needing clean up from ruts and over growth and brush cleared it's 44 acres with a combination of flat land and hills. Terrain is rocky, we are in northern CA gold country where placer mining was done so lots of smaller rocks in the soil and piles of cobble rock from mining tailings. Here's the dozer's details, the D7 has near new condition undercarriage, good running pony and engine and is a cable dozer. Looks to be kept up well, even newer paint. D6 has worn undercarriage, high pin wear, decent tracks. Pony and engine both run good. It's a hydraulic blade. Turning on the D6 is fair but the lever and brake must both be applied full travel to turn but does turn both directions, could be way out of adjustment, or needing parts replacement. D7 turns fine. Seeking opinions on which might be a better unit in the terrain I'm going to put it to use in, I need to keep the roads and firebreaks up yearly, and clear the overgrowth of brush on the property then maintain it. Any input would be greatly appreciated. I regularly operate heavy equipment just not dozers.

Coaldust · Mar 25, 2021

One is none and two is one.
Get both!

Bluox · Mar 25, 2021

Run Forrest run as fast as you can they are 65 + years old .
Bob

Coaldust · Mar 25, 2021

Dozer Newby,

I invite you to head over to the new member forum and introduce yourself.
BTW, Welcome!

Dozer Newby 2021 · Mar 25, 2021

Bluox said:
Run Forrest run as fast as you can they are 65 + years old .
Bob

Seriously ? A neighbor has a D8 from the 60's or older I believe and he has used it since we bought this land in 1973, he still uses it to this day, but I'm sure like us once the initial clean up is done the yearly hours would not be high. But if you think that old dozers are junk I'll take that into consideration. We plan on keeping what ever we buy, store it inside and maintain it, pass it to the next generation that are in their early 20's now. D6 or D7 seem built like battleships to me compared to the modern stuff we have at my job. No electronics to go out or get obsolete in 2 years. You really think they are that much a waste of consideration ?

Dozer Newby 2021 · Mar 25, 2021

Coaldust said:
One is none and two is one.
Get both!

If I had to choose on condition the D7 wins but it's a cable dozer. The D6 will need undercarriage parts, a couple hydraulic hoses, seat recovered and fix it's turning ability whether adjustment or parts. The D7 is work ready. Don't know how they stack up against each other performance wise though in equal condition.

Coaldust · Mar 25, 2021

They are old-school cool. The D7 will never leak hydraulic oil on your back forty.

old-iron-habit · Mar 26, 2021

Bluox said:
Run Forrest run as fast as you can they are 65 + years old .
Bob

That's the best thing about them. They were built to last.

old-iron-habit · Mar 26, 2021

Dozer Newby 2021 said:
If I had to choose on condition the D7 wins but it's a cable dozer. The D6 will need undercarriage parts, a couple hydraulic hoses, seat recovered and fix it's turning ability whether adjustment or parts. The D7 is work ready. Don't know how they stack up against each other performance wise though in equal condition.

The 3T D7 will out push the 9U-D6 by a fair margin. The 3T and the 9U were two of the best, most reliable Cats ever made. I sold my cable 2U-D8 just last week to a contractor that still uses one just like it weekly. I am still crying in my beer for selling my cable 9U-D6 a number of years ago. Cable will do all you need to do in fine style and is easy to maintain. Just never, ever, try to adjust the CCU with the engine running. Check out the ACMOC site where all the Cats are pre-60s. Lots of good folks and advice there. Get manuals and read them and they will run forever.

DB2 · Mar 26, 2021

If you have your heart set take the 7 as it steers properly, has a better undercarriage, and it doesn’t sound like moving it around is going to be an issue. Cable works fine if maintained.

Dozer Newby 2021 · Mar 26, 2021

DB2 said:
If you have your heart set take the 7 as it steers properly, has a better undercarriage, and it doesn’t sound like moving it around is going to be an issue. Cable works fine if maintained.

Is there any best kind of grease to use on the cable pullies or the rest of the dozer for that matter ?

Joel59 · Mar 26, 2021

They are both good old dozers. As BlueOx mentioned- they are old. That being said, not everyone can afford a new machine. They are big money. I still run my old 9U and, at times, get paid to do so. It has paid for itself over and over again. However, I do my own work to it, and have the ability and willingness to do so. As most will explain to you, the value in these old machines is in the undercarriage. I would go with the 7 based on that. No matter which one you choose, just be realistic and understand that you aren't going to hop on the machine day in and day out without breakdowns. Good luck.

Bluox · Mar 26, 2021

Dozer Newby 2021 said:
Seriously ? A neighbor has a D8 from the 60's or older I believe and he has used it since we bought this land in 1973, he still uses it to this day, but I'm sure like us once the initial clean up is done the yearly hours would not be high. But if you think that old dozers are junk I'll take that into consideration. We plan on keeping what ever we buy, store it inside and maintain it, pass it to the next generation that are in their early 20's now. D6 or D7 seem built like battleships to me compared to the modern stuff we have at my job. No electronics to go out or get obsolete in 2 years. You really think they are that much a waste of consideration ?

If you think grease is a hard question here are a few reality checks.
That tractor has 5 or 6 clutches and brakes that need regular adjustment.
Have you ever ran a big tractor with a clutch?
Have you ever dealt with wire rope?
Do this have a wet or dry clutch? A steering booster? Are track adjuster hydraulic or manual? Are track rollers life time lube or greased?
I'm kind of a beginner at this I've only worked on tractors for a little over 50 years and seen this same scenario played out 100 times or more.
A homeowner buys a big old wore out tractor then dumps large piles of cash in it .
These machines are becoming harder to find hard parts for and every thing on it is heavy.
But its your circus and your monkeys so carry on .
Good luck
Bob

old-iron-habit · Mar 26, 2021

As Bluox stated, there is maintenance to do, more than in a newer machine. How handy are you. If you buy a set of manuals which are easily found on E-bay, read them, and can follow quite simple instructions, you will be fine. Not sure what you operate but they are not real difficult to learn by anyone with a bit of a knack for machinery. You are not building a golf green. The 3T will have a very good probability of a dry clutch. They need occasional adjustment when working as well as proper lubrication all simple as explained in the manuals if you have basic mechanical knowledge. The 9U could have a wet or dry clutch, dependent on year. Parts are still fairly common for both. There are thousands of used parts machines out there, and Cat still sells some of the more common ones. Again, ask all the pertinent questions on the ACMOC board. You will get a lot of opinions to mull through the same as here, so you can make a qualified decision. Good luck.

Dozer Newby 2021 · Mar 26, 2021

Bluox said:
If you think grease is a hard question here are a few reality checks.
That tractor has 5 or 6 clutches and brakes that need regular adjustment.
Have you ever ran a big tractor with a clutch?
Have you ever dealt with wire rope?
Do this have a wet or dry clutch? A steering booster? Are track adjuster hydraulic or manual? Are track rollers life time lube or greased?
I'm kind of a beginner at this I've only worked on tractors for a little over 50 years and seen this same scenario played out 100 times or more.
A homeowner buys a big old wore out tractor then dumps large piles of cash in it .
These machines are becoming harder to find hard parts for and every thing on it is heavy.
But its your circus and your monkeys so carry on .
Good luck
Bob

Dozer Newby 2021 · Mar 26, 2021

I'm new to dozers, that's why I joined this forum to learn. I am not new to heavy equipment or mechanics , and I have a well equipped shop. The undercarriage on this D7 was replaced and not long ago so that's not my worry, the rollers are manual greased type. Have to get a manual to learn the clutch adjustments and brake adjustments, they seem to be adjusted ok at this time the dozer turns good both directions. I don't know if it's a wet or dry clutch, or if it has a steering booster, nor do I know if the track adjusters are hydraulic or manual. All good questions I need to find out the answers to. I've been printing out tips on properly adjusting the cable blade when the time comes that it needs it right now it works fine. Need to learn about repairing the cable if needed as well. I think I can eventually figure all this out, I've been a car builder since 1975 as well as having a commercial license and driving every kind of semi and modern equipment most cities and counties own. The pic I posted is my Bonneville race truck I've owned 29 years, it has 2 overdrives, 2 completely different engines and I did the complete frame off build on this and about 2 dozen others over the years so I know I can eventually figure the D7 out, I'm just hoping to pick the brains of guys like you that have been doing this forever and can help me avoid costly mistakes. I've found over the years there's owners that care about their equipment and go above and beyond taking care of it, and there's those that do the minimum, and those that run them into the ground. I've spent the past year looking and I've seen all the different types for sale, most are worn out. This D7 is the best I've seen so far. So thank you to everyone for your input, it's all appreciated, and all taken into consideration. Yeah it's old, so am I . Just like I try to work smart today & not abuse my old body I would do the same with any dozer, not abuse it, I've got time, smaller pushes, smaller bites. I'll save the hurry up stuff for the race car. I'll get some manuals asap. Did find a good parts supplier up in Boise, Idaho.

old-iron-habit · Mar 27, 2021

Dozer Newby 2021 said:
I'm new to dozers, that's why I joined this forum to learn. I am not new to heavy equipment or mechanics , and I have a well equipped shop. The undercarriage on this D7 was replaced and not long ago so that's not my worry, the rollers are manual greased type. Have to get a manual to learn the clutch adjustments and brake adjustments, they seem to be adjusted ok at this time the dozer turns good both directions. I don't know if it's a wet or dry clutch, or if it has a steering booster, nor do I know if the track adjusters are hydraulic or manual. All good questions I need to find out the answers to. I've been printing out tips on properly adjusting the cable blade when the time comes that it needs it right now it works fine. Need to learn about repairing the cable if needed as well. I think I can eventually figure all this out, I've been a car builder since 1975 as well as having a commercial license and driving every kind of semi and modern equipment most cities and counties own. The pic I posted is my Bonneville race truck I've owned 29 years, it has 2 overdrives, 2 completely different engines and I did the complete frame off build on this and about 2 dozen others over the years so I know I can eventually figure the D7 out, I'm just hoping to pick the brains of guys like you that have been doing this forever and can help me avoid costly mistakes. I've found over the years there's owners that care about their equipment and go above and beyond taking care of it, and there's those that do the minimum, and those that run them into the ground. I've spent the past year looking and I've seen all the different types for sale, most are worn out. This D7 is the best I've seen so far. So thank you to everyone for your input, it's all appreciated, and all taken into consideration. Yeah it's old, so am I . Just like I try to work smart today & not abuse my old body I would do the same with any dozer, not abuse it, I've got time, smaller pushes, smaller bites. I'll save the hurry up stuff for the race car. I'll get some manuals asap. Did find a good parts supplier up in Boise, Idaho.

You race truck is more than cool. If you can build that, you can figure out a 3T in short order. What did it run at Bonneville? Are you going back? I'd love to be there to see and hear you run.

Dozer Newby 2021 · Mar 27, 2021

old-iron-habit said:
You race truck is more than cool. If you can build that, you can figure out a 3T in short order. What did it run at Bonneville? Are you going back? I'd love to be there to see and hear you run.

Bonneville has not held a "Thrusted Class " event in a long time, jets and rocket powered vehicles mess up the surface for the regular cars so haven't run there yet. The front engine is a supercharged 521 cid Ford, makes a little over 1000 horsepower, the rear engine is a Bob Maddox pulse jet engine, a stainless steel copy of the WW2 German V-1 cruise missile engine, it makes 1000 lbs of thrust. Bob Maddox is the jet go to guy for the TV shows "Myth Busters " and Jessie James "Monster Garage " . My father worked on missiles at Douglas Aircraft in the 50's & 60's and my cousin is a engineer at NASA, Florida, so this project had expert input. Bob has been trying to set up a thrusted event in Oregon for a couple years now, that's where he does his testing. Truck runs a Toploader overdrive transmission back to a Mitchell overdrive to a 9 inch rear with 2.47 gears. You think dozers get bad fuel mileage the pulse jet burns 9 gallons a minute at full throttle requires multiple huge Aeromotive fuel pumps to keep it fed. Has a 3 minute fuel supply from a tank under the bed. It also ingests NOS through it's special dual side draft intakes. I actually keep license plates and insurance on it and take it out to car shows once in awhile, just don't turn on the pulse jet that's a ticket to jail.

old-iron-habit · Mar 27, 2021

Dozer Newby 2021 said:
Bonneville has not held a "Thrusted Class " event in a long time, jets and rocket powered vehicles mess up the surface for the regular cars so haven't run there yet. The front engine is a supercharged 521 cid Ford, makes a little over 1000 horsepower, the rear engine is a Bob Maddox pulse jet engine, a stainless steel copy of the WW2 German V-1 cruise missile engine, it makes 1000 lbs of thrust. Bob Maddox is the jet go to guy for the TV shows "Myth Busters " and Jessie James "Monster Garage " . My father worked on missiles at Douglas Aircraft in the 50's & 60's and my cousin is a engineer at NASA, Florida, so this project had expert input. Bob has been trying to set up a thrusted event in Oregon for a couple years now, that's where he does his testing. Truck runs a Toploader overdrive transmission back to a Mitchell overdrive to a 9 inch rear with 2.47 gears. You think dozers get bad fuel mileage the pulse jet burns 9 gallons a minute at full throttle requires multiple huge Aeromotive fuel pumps to keep it fed. Has a 3 minute fuel supply from a tank under the bed. It also ingests NOS through it's special dual side draft intakes. I actually keep license plates and insurance on it and take it out to car shows once in awhile, just don't turn on the pulse jet that's a ticket to jail.

That is just flat wild. Post a video of it running sometime if you can.

D7 3T VS D6 9U

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