The Cat® D10: Generations of Pride

Generations of Pride

The Cat® D10: Generations of Pride

Since it was introduced in 1977, the Cat® D10 has been one of the most popular large dozers in the world. Over the ensuing four decades, thousands of Caterpillar employees have been involved in the D10s design, upgrades, sales and service. Here, two Caterpillar engineers — one currently employed by Caterpillar and one retired from the Caterpillar Tractor Company — discuss the pride they feel for their roles in the history of this revolutionary and enduring machine.

Starting A Revolution

Eldon Oestmann, Caterpillar Design Engineer - Retired:
The D10 started out as an assignment that we couldn’t complete with existing technology. Large customers, mostly miners, had been asking for a large dozer that had more ripping power and could move more dirt than the D9. But we were already having issues with the D9s undercarriage in some applications and a larger tractor would have only made those problems worse.

Loren Vincent, Caterpillar Application Specialist - Large Tractor Group: 
Before the advent of large dozers like the D10, the tractor designs were for farm-based applications. Go back to the ‘20s or ‘30s and there weren’t really any ground-engaging tools for them. As we started to put on the blades and rippers, we had to start think about them as production dozing machines.

Eldon: Rather than trying to design an undercarriage that could take the loads generated by a larger tractor, we decided to see if we could come up with a design that would reduce those loads.

I sketched up what a tractor with a suspended undercarriage might look like. We found that relocating the sprocket up high to accommodate the undercarriage opened up all kinds of opportunities in the powertrain. It also allowed us to completely change the way components were attached to the machine.

A Good Idea Gets Better

Loren: It’s amazing to think that Eldon and his team developed the high-drive and the suspended undercarriage using just slide rules and intuition. Even without the computer design tools we have today, those developments helped us understand that the operators have the biggest impact on the performance of our machines. Very quickly, we saw improved operator efficiencies.

Eldon: The new design made servicing the machine a lot easier, too. We were able to lower the transmission and engine, which resulted in a lower center of gravity despite its taller apparent stance. We were also able to move the transmission to the rear, which allowed the transmission to be pulled for service without disassembling the track.

We found one idea after another that produced better capabilities: better sight lines with an angled seat, lower noise levels from the relocated engine, more digging power with vertical cylinders. There was lots of serendipity.

Loren: As the D10 has evolved, there has been even more focus on operator efficiency. For example, we went from mechanical levers to electrical joysticks that produce a lot less fatigue. We’ve introduced lots of features that help to improve operator comfort and efficiency so our customers can get a lot more out of the machine than they could in previous generations.

Two Proud Parents

Eldon: The day the first D10 rolled off the line was a great day. We knew that customers were excited about it. Today still, the D10 has a special spot in my heart.

It’s kind of like having a child. You bring it up and you mold it and you send it out into the world to see if it works or not. You’re always interested in what it’s doing out there and how well it’s doing. We probably didn’t understand how big an impact the D10’s design would have. We were just joyful that our baby was growing up and becoming successful.

Loren: I totally understand that. I look at the Cat D10 today as my baby.  I went through the D10T2 New Product Introduction program from beginning to end. When you finally get a machine like that into production, you realize that not a lot of people get the opportunity to do something so important.

There’s a lot of history with the large Cat track-type tractors and the D10 plays an important role.

Eldon: Seeing a D10 in the field today gives me a feeling of some sort of immortality.  Your ideas are continuing. I have a tendency to salute every time I see a large Cat machine.

Loren: When I go out to trade shows these days, I love when people ask me what I’m working on because I get so excited about it.  I can say, “I help to sell the largest bulldozers that Caterpillar makes: the D10 and D11—154,700 and 229,900 pound machines.” It’s a great feeling.

The Legacy Lives On

Eldon: Thanks to Loren and the rest of the Caterpillar Large Tractor Group, the D10 continues to get better and better. I feel that any machine needs to change and be updated with new technology at least every fifteen years. I want to see it constantly develop. I want to see it constantly improve.

The fact that other Cat dozers have followed in the footsteps of our design shows that we did a lot of things right.

Loren: When I retire like Eldon did, I want to make sure I leave my own legacy in the D10s story. If there’s anything we can do in our group to continue to keep it an industry leader, we want to do it.

The D10 has been through a long journey. We want to do the right things to continue that journey for a long time.


Whether developed using slide rules or super computers, Cat equipment is engineered with pride and a deep commitment to helping our customers succeed in the important work they do. That commitment began over a century ago and has never wavered. With the talents and dedication of people like Eldon and Loren, along with thousands of others worldwide, we promise that it never will.

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