It is a common knowledge that no Suzuki vehicle has a lockable axle differential. However, there are a few important exceptions.
Factory rear differential locker
LJ80, SJ410 and early SJ413 vehicles sold in Germany (and perhaps in some other countries as well?) were fitted from the factory with a manually operated, mechanical rear differential locker. A cable connected the locker to a small dedicated lever in the cabin near the hand brake lever. By operating the lever, the driver could manually fully (un)lock the rear differential.
The reason for inclusion of the differential locker was legislative in nature. LJ80s, SJ410s and early SJ413s had a parking brake which brakes the gears in the transfer case instead of braking the individual rear wheels directly and simultaneously (like in most passenger vehicles). That design has several advantages, as well as an important disadvantage - because of the open rear differential, the hand brake has no effect when the transfer case is in two wheel drive (rear wheel drive) mode and when one of the rear wheels is raised in the air. Therefore, relying on the parking brake itself would be dangerous in some relatively rare situations. German law required that this risk must not exist.
Instead of redesigning the parking brake system for that market, Suzuki appeased the legal requirement by the inclusion of a rear differential locker.
Later SJ413s (and all Samurais) have a parking brake which simultaneously brakes both rear wheels directly (like in most passenger cars), so the parking brake alone could hold the vehicle still in any situation, at least in theory. This parking brake design appeased the German legal requirement, and therefore no differential locker has been factory fitted to such SJ413s nor to any Samurai, nor offered as an optional equipment.
A retrofit of a genuine rear differential locker to LJ80s, SJ410s and SJ413s which lack it is possible by using the parts from a dismantled LJ80 (usable on another LJ80 only), SJ410 or early SJ413 (usable on both SJ410 and SJ413) which had that locker. A retrofit from SJ41x is not easily possible onto a Samurai because of wider track / axle than SJ41x.
Page last edited on 12/01/2021 by user Bosanek