DIFF DROPS MADE SIMPLE

WE BRIEFLY touched on the topic of diff drops, and with live-axle 4x4s becoming more and more irrelevant it’s a term you’ll be hearing a lot more of in the future. So what exactly are they? They fundamentally come down to CV (constant velocity) joint angles. When you lift a live-axle 4x4 the vertical distance between the transfer case output and the diff centre increases, as it goes up the driveshafts become angled. As they’re normally long it’s very rarely an issue, as the angles are more than safe enough. In an IFS or IRS 4x4 this same situation happens, although as the diff centre is bolted to the chassis the angle change is in the CV joint rather than the driveshaft. As these shafts are significantly shorter than a driveshaft, any change in height is amplified, making the CV operate on angles out of its optimum strength. A diff drop is either a bolt-in or weld-in bracket arrangement that drops the diff centre away from the chassis to correct these angles and return some strength into the CV joints. They’re a simple and low-tech upgrade, but one that’s required if you don’t want to replace CV joints every few thousand kays.