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SA4x4 Clinic got a technical query

Locker Front Or Back?


Qusetion by: Corné Opperman Answer by: Ronald HairbottleI drive an ‘84 Nissan Patrol SWB. It has a limited-slip diff at the rear and nothing up front. If I were to fit a diff-lock to this vehicle would it be advisable to put it at the rear, or should it be installed up front?
If fitted to the front, will the locker affect my vehicle’s turning circle? Also, in terms of diff-locks, what options do I have for the Patrol?
Corné Opperman

The efficiency of your current limited-slip diff (LSD) will be marginal, now that the vehicle is 26 years old. The reason for this is that the clutch packs within the LSD wear out over time and distance, thus rendering the unit inoperable and not much more effective than an open diff.
We always advise our clients to first install a locker in the rear diff. The general consensus is that your 4×4 has a 70 percent traction advantage at the rear and only 30 percent up front, due to weight transfer shifting to the rear axle on an upward slope. So naturally, it’s advisable to install a locker where maximum traction is to be had.
If your Patrol has the H233B axle with 31 spline side shafts, you can fit a Detroit Automatic Locker at the rear. This unit automatically locks and unlocks, and requires no driver intervention. Pricing is affordable and installation a breeze. What’s more, because this locker features minimal working parts, it’s incredibly reliable. There are some on-road handling quirks to get used to but in my opinion these are barely noticeable thanks to the Detroit’s internal synchroniser rings, which make the differentiation process transparent.
You can also install an ARB Air Locker, which will require the installation of an onboard air compressor. Once again, we advise that this locker be fitted to the rear diff, not only for the traction advantage but because a front locker installation will adversely affect your vehicle’s turning circle, requiring you to disengage the locker before making a tight turn.
Ronald Hairbottle
TAC 4×4 Traction
(015) 293-0736 / 082 376 5378