The Cat D12, Myth, Legend, or Reality?

For many years there has been talk of a potential D12 dozer from Caterpillar. While officially we haven’t seen anything from the manufacturer, but one Australian contractor has a long history of modifying large Cat tractors to suit their requirements, and has come up with its own version.

Over the weekend I came across a series of photos posted on our old mate Michael Bullock’s Instagram page aka @the_english_earthmover, the photos were originally taken by Lawrence Lowe who shared them with Michael for his page.

As Michael wrote, D12’s Do exist! but only in Queensland, Australia though. My interest was raised and I figured it would make for a great blog post to kick off the week.

It transpires that Queensland based Mearns Hire, who were established in 1965, have modified four of their Cat D11 models for their work which involves blade ploughing outback hardpan, cutting the roots off scrub, and re-seeding.

To enable this, they take a D11R or N model, remove the standard 850hp (V8) engine, stretch out the chassis, making it longer to give them the extra space to shoe horn in a Cat 3512 (V12) engine taken from a giant Cat 785 dump truck.

This configuration bumps the power up to an impressive 1250hp. The same D11 transmission is used, but they utilise the trucks torque converter and lock up clutch arrangement.

They use the standard radiator for coolant, but install a secondary transmission oil cooler which is mounted up on top of the ROPS frame, it looks a bit odd, but it is necessary as they tend to run this beast in 2^nd gear all day pulling the 10m wide blade plough.

I echo Michael’s sentiment when he says this is an incredible piece of Aussie engineering designed to meet the specific needs of this company working in some of the harshest conditions on earth.

Checkout this brief video clip of the machine in action below.