For many years, there has been speculation about a potential D12 dozer from Caterpillar. Although the manufacturer has yet to release anything official, one Australian contractor, known for customizing large Cat tractors to meet their unique needs, has developed their own version.
Over the weekend, I came across a series of photos on Instagram posted by our old mate Michael Bullock, also known as @the_english_earthmover. The photos, originally taken by Lawrence Lowe, were shared with Michael for his page.
As Michael noted, D12s do exist—but only in Queensland, Australia! Intrigued, I thought this would make a great blog post to start the week.
It turns out that Queensland-based Mearns Hire, established in 1965, has modified four of their Cat D11 models for specialized work, including blade ploughing outback hardpan, cutting scrub roots, and re-seeding.
To achieve this, they start with a D11R or D11N model, remove the standard 850hp V8 engine, and extend the chassis to create enough space for a Cat 3512 V12 engine, sourced from a massive Cat 785 dump truck.
This setup boosts the power to an impressive 1250hp. They retain the original D11 transmission but incorporate the truck’s torque converter and lock-up clutch system.
For cooling, they use the standard radiator but add a secondary transmission oil cooler mounted on top of the ROPS frame. Although this placement looks a bit unusual, it’s essential, as they typically run this powerhouse in 2nd gear all day while pulling a massive 10-meter-wide blade plough.
I share Michael’s admiration for this incredible feat of Aussie engineering, designed to tackle the unique demands of a company operating in some of the harshest conditions on earth.
Checkout this brief video clip of the machine in action below.
