Ouch. That familiar sound – and the painful gritting of the teeth that go with it – are all too common off-road. We put our machines through their paces every time we hit the dirt, and especially so if you’re into the tougher, more challenging side of 4WDing.

If you’re not a big fan of bush fixes and repair bills, then a simple couple of checks underneath your 4WD can mean the world of difference next time you head out bush. Graham’s been punting the 4WD Action D-MAX around Tassie recently, and we figured this was the perfect time to talk about how to get a better understanding of your undercarriage. These easy tricks will save you serious time and money!


If your 4WD’s within spitting distance, go out right now and hop down underneath for a good look – and we mean a really good look. Take note of the various low-lying components – the gearbox and the even-lower (in most cases) transfer case, the suspension arms, the diffs. These are the bits that stop you from moving when you get caught up on a tree root, a rock or a rut. Take note of what hangs the lowest, and where each of these components are in relation to each tyre. Then, next time you’re on the tracks, keep these components in mind and do your best to pick a line that misses the biggest obstacles altogether. It’s exactly what Graham does when he’s driving the D-MAX, and it’s one of the reasons why the relatively standard dual-cab keeps up with Shauno and the boys in their monster trucks. The Terrain Command transfer case sits relatively high, and Graham’s got the bonus of a steel bash-plate to protect it from the odd knock on a rock. Which brings us to…


The best thing you can do for your undercarriage is pick a line through an obstacle that keeps your lowest-hanging components clear from rocks and ruts. The simplest and most-effective way to do this, involves putting your tyres up on the high-points on the track, to create as much clearance for the rest of your undercarriage as possible. You can see Graham do this with the D-MAX frequently – running 31inch mud tyres, it doesn’t have the under-body clearance of the 35inch-tyred bigger trucks, but a bit of smart line selection means that makes no difference at all. There is one downside to this technique, though.


Putting tyres over high-points in the track can quickly reach the limits of your suspension’s travel, which will then lift wheels and stop you moving forward. The solution then is a diff lock or two, or something like a Traction Control System, but what if you don’t have any traction aids? Simple – it’s time to put on the high-vis (just kidding) and start with the road-building. Rocks, branches, logs, traction boards – whatever you can do to fill the low-spots and keep your suspension from having to extend as much, will massively help here. Ten minutes of hard sloggin’ and getting a bit of dirt underneath the fingernails will make a huge difference to how far you can drive.


Ever wondered why the best off-road drivers take things slowly? It’s because they’re testing the waters on their first attempt at a track. Sometimes it works, and you come off looking like the off-road chap of the world because you just crawled your way up a section of tough terrain first go. But, if it doesn’t work, and you get a spring hanger, diff or transfer case caught somehow, you usually can just back out of it. That is, unless you’re going so fast that you high-centre yourself with wheels spinning in the air. Take it slow, and if you do get caught, just try a different line.


Under-carriage clearance can only ever be increased by fitting bigger tyres, but here’s a bit of a secret for everyone driving a 4WD with Independent Front Suspension (IFS), like the 4WD Action D-MAX. Put an IFS 4WD and a solid axle 4WD side-by-side on the same sized set of tyres, and the IFS vehicle will have considerably better clearance under the front diff. The design of the diff means the diff centre doesn’t have to sit down on the same plane as the wheel hubs, meaning you’ll find your IFS 4WD can clear bigger rocks and ruts than a comparable solid-axle Patrol or Cruiser. There’s some ammo to fire back the next time the solid-axle v IFS debate fires up at camp! [share title=”Share this Post” facebook=”true” twitter=”true” google_plus=”true” linkedin=”true” pinterest=”true” reddit=”true” email=”true”]