Lockers are one of those things that you don’t fully appreciate until you need them. At a basic level, a differential lets the wheels on the same axle spin at different speeds — which is great for normal driving, cornering, and pavement. But off-road, that can be a problem. If one wheel starts spinning in the air or loses traction, all the power goes there, and you get stuck. That’s where lockers come in. A locking differential forces both wheels on an axle to turn together, giving you traction when you need it most.
On my 2019 Z71 Colorado, I’ve got the G80 auto locker in the rear. It’s a solid system — when one wheel loses traction, it locks automatically and keeps me moving. The convenience is nice, and it works most of the time without me thinking about it. The downside? Because it engages automatically, it can be a little unpredictable on tight, rocky trails. You feel the truck tug and bind when it locks up, which can be unnerving if you’re not expecting it. Overall, though, it’s a huge advantage over an open diff, especially in mud, snow, or uneven terrain.
My 1991 Blazer, on the other hand, has open diffs front and rear. That’s been fine for cruising and light trails, but I can definitely feel the limits when traction gets tricky. I’ve been planning to add an OX locker to the rear and swap the gears from 3.42 to 3.90 — that combination will give me more control and power off-road. I’ve also thought about adding a limited-slip to the front and rear — something like a Truetrac — but I really like the idea of a selectable rear locker, so I can choose when to lock and when to drive normally.
Sometimes I look back and think about the ZR2 Colorado I didn’t get. The front and rear selectable lockers would have been amazing, especially on technical trails. At the time, I didn’t fully appreciate how important lockers are, and I wasn’t as invested in off-roading. Now, every trail reminds me that those extra lockers would have made a noticeable difference.
At the end of the day, lockers aren’t magic — you still need to drive smart — but they give you options you don’t get with open diffs. Open diffs are simple and fine for most driving, but a locker can be the difference between spinning in place and making it through a tricky section. For anyone getting into serious off-roading, understanding the diff setup on your truck — and what options are out there — is a big part of being prepared.