Why This Weird-Looking $5000 Military Tug Could Out-Crawl Off-Road Vehicles Costing 10 Times As Much

I really need to buy this military tug, and honestly, so do you. Do I live in a one-bedroom apartment with limited parking? Sure. Is this tug even street legal? No. Do I own an airplane that needs to be moved around? No. Is the $4,850 asking price a little dear for a cheap bastard like me? Sure. But none of this matters, because I can easily, easily rationalize this purchase. You see, what you’re looking at is an amazing starting point for a budget, Moab-crushing, rock-crawling beast. Hear me out!

I’ve been drooling all over my keyboard these pasts few weeks staring at this 1975 Coleman “G-40” military tug for sale in Las Vegas:

Obviously, I like it because it’s incredibly cute, with its tall roof but ridiculously short wheelbase, and its hilariously skinny hood. Everything is so squared off, and the tires are just so gigantic; it all looks so stubby and awkward, and I just can’t get enough! But this tug has a lot more to offer than just great looks.

Under the hood is a Chrysler 318 cubic-inch V8 motor sending gobs of torque to all four wheels, which are all steered hydraulically! That’s right, this little tug is essentially a V8, four-wheel drive pickup with four-wheel steering!

Since I’m sure you’re wondering how that looks when it’s functioning, the answer is: Amazing. In fact, you can watch the glorious four-wheel steering in the video below uploaded by Low Buck Garage. This YouTube channel is run by a guy named James, whom I interviewed and wrote an article about last year. James is my Jeep hero, so I find it hilarious that he already owns this really irrational machine that I recently found myself lusting over:

At the end of the video above, James asks the question I asked myself upon finding the Facebook Marketplace listing: What do I do with it? The answer is actually quite simple: Turn it into an off-road rig. The thing already comes with 40+-inch tires, it has short overhangs, a small wheelbase, four-wheel drive, and absurd gearing. It’s a fantastic starting point for a rock-crawler.

I just found the official technical manual for this tug, and my god is it a deep rabbit hole.

Look at this lovely diagram!:

The basic setup is this: There’s an “industrial type” Chrysler V8 motor hooked to an Allison four-speed automatic transmission, a transfer case (which provides a 2.6:1 gear reduction and splits power off to the front and rear axles — it includes a differential that can be locked), and leaf-sprung solid axles with between a 6.2:1 and 7.2:1 gear reduction (depending on the exact Coleman G-40 model).

Let’s pause there for a second. A 7.2:1 axle ratio, a 2.6:1 low range reduction, and a transmission with a 3.45:1 first gear ratio — that all multiplies out to a 65:1 crawl ratio. That 140 horsepower V8’s motor makes 220 lb-ft of torque, which gets multiplied by 65 by the time it gets to those 11.00-20 tires (those are 43 inches). A modern Jeep Wrangler Rubicon has a numerically larger crawl ratio at over 90:1, but still, 65:1 is decent; this airport tug should have plenty of tugging “power,” and that means it’d make for an excellent low-speed rock crawler.

Obviously, at 11,000 pounds, it’s a bit large to be amazing off-road, but 12 inches of ground clearance at each axle is solid. The eight-foot overall height, huge bumper up front, and low-mounted draw bar out back are a little concerning for off-roading, but some plasma cutters could take care of those to reduce the risk of rollover and improve the approach and departure angles a bit.

More importantly, we need to talk about the steering system, because it’s cooler than you think. First off, the G40 has a better steering radius than pretty much any car on the market, including the no-longer-on-the-market BMW i3, which has hilariously skinny tires and turns on an absolute dime. The i3’s turning radius is 16.2 feet; the G40 tug’s turning radius? 15 feet! Even more incredible is the fact that the front and rear axles turn independently. Seriously, read this:

Here, let’s watch another video of this amazing steering system in action:

Here’s a diagram of the hydraulic steering system showing the hydraulic steering cylinders for each axle:

For you nerds out there, here’s the G40’s full “table of specifications”:

Top speed, as you can see, is just 24 mph in fourth gear, but for an off-road rock-crawler, that’s all one needs.

The more I read the G40’s technical manual, the more I’m convinced that this tug might be the ultimate starting point for a cheap off-road buggy build. Seriously, check out this little bit of info about the axle shafts: “These axles have one-piece forged axle shafts that can be readily removed without lifting (jacking) the tractor.”

Forged shafts! And easily replaceable!

Obviously, the heft and size are an issue, and parts availability can be tough, but with some weight reduction methods, this $4,850 tug could be a great way to build an off-road buggy without spending a fortune. Seriously, a set of Dynatrac axles for a Jeep can cost well over $10,000; a lift kit other provisions needed to fit 40-inch tires on a Jeep Wrangler also costs lots of money.

But the Coleman G40 is ready out-of-the-box: It’s built to handle 43-inch tires, it’s got decent gearing for crawling, it’s got an absurdly tight steering radius to help you navigate tight trails, its overhangs are short enough right out of the box (and can be reduced; looks like that bumper will come right off), and most importantly: it’s cheap.

[Edit: As some have pointed out, I’ll want to throw some new, taller springs on it to give it some wheel travel. This will likely require some modifications to that amazing steering system. -DT] 

And you know I love cheap.