Join Date: Jun 2016
Location: Newcastle, Australia
A locking rear diff is a tool for a purpose. If you don’t have a need for it, it’s a waste of your money.
For on road safety, electronic traction control is the most effective tool available. It’s also excellent off-road if appropriately calibrated for off-road use (Nissan are traditionally excellent at this). Off-road, ETC does not compromise steering or strain on the axles like a diff lock does.
Diff locks become useful when you encounter scenarios where one wheel leaves the ground. This is obviously more likely on the rigid rear axle and why most factory fitments only fit to the rear (I can count on one hand to be number of factory-fitted front diff locks in production today...)
The best combination is to have both, traction control and a diff lock. Unfortunately, traction control ceases to work on a locked axle, and with an ARB locker, this may cause the traction control to turn itself off completely on both axles when the diff is locked (the Nissan factory-fit diff lock keeps traction control running on the front axle, which is fantastic).
So in summary, if you have traction control and you’re not 100% sure you need a diff lock, you don’t need one. Invest that money in some good off-road tyres or nice long-travel springs and avoid losing grip to begin with.
PS - as the LSD usually takes different fluid to the open diff, someone who knows what they’re looking at should be able to tell by simple visual inspection. It probably left the factory with a sticker on it, but this is presumably long gone by now.