Offroad-Express

I have a 185 series Hilux Surf that i was looking to install a locking rear diff of some kind. I have a LSD centre in the shed already, and intend to fit that, but heaps of people say that the factory ones are rubbish.
I mainly require it for soft, muddy paddocks. The ARB or Ironman locking diffs are probably overkill( financially) given my infrequent needs. I'm not that sure of the lokka/lock rite type of diff , simply due to the change in character on road(it gets driven by various people, not just me).
So for my purposes, will a factory LSD suffice? will shimming it tighter improve its off road performance? should i have a solid pinion spacer installed? (these are things i've had done to a hilux diff installed in a turbo race vehicle, but are these mods of any use in a 4WD application?)
Thanks for any help. Cheers.

BlakeNZ wrote:I have a 185 series Hilux Surf that i was looking to install a locking rear diff of some kind. I have a LSD centre in the shed already, and intend to fit that, but heaps of people say that the factory ones are rubbish.
I mainly require it for soft, muddy paddocks. The ARB or Ironman locking diffs are probably overkill( financially) given my infrequent needs. I'm not that sure of the lokka/lock rite type of diff , simply due to the change in character on road(it gets driven by various people, not just me).
So for my purposes, will a factory LSD suffice? will shimming it tighter improve its off road performance? should i have a solid pinion spacer installed? (these are things i've had done to a hilux diff installed in a turbo race vehicle, but are these mods of any use in a 4WD application?)
Thanks for any help. Cheers.

I run a shimmed LSD in my winch challenge zook (lux axles) and its mint when its tight, after 3 or so years of club trips and racing (sees no road use) its getting a bit slack again. So I guess for your purposes if you can pull every couple years and tighten it then all good. Solid spacer is a good mod.

When you guys say shim, do you mean adding more clutch discs/friction discs or literally adding a spacer to the bottom of the clutch pack??

It's not adding more plates, so i assume it is the latter. They measure the "breakaway" force ( i imagine with a torque wrench) before and after they tighten it up. Increases of 50 to 100% are possible, depending on the wear condition of your existing diff.
I can't tell you exactly what the breakaway force means, sorry.

There is two ways to shim them the lazy way is to put a washer on the center spring in the little box in the middle this dramaticly increases brake away torque
I have seen slippery housings where this has broken the centre housing and don't do it unless I'm specificity asked
The other way is to measure all the shims compare them to factory standard and cut a shim (from shim steel) to set them to the tight side of that standard or slightly tighter you then drop the shim in the bottom of the housing where it dosn't move
So long as you haven't adjusted the pinion flange nut setting the diff back up is easy just a case of setting the backlash on the gear by adjusting the carrier bearings

Breakaway torque is the torque required to spin one wheel whilst hold the other wheel still (pinion needs to be free to rotate).

Jack up one wheel, put transfer case in neutral, put torque wrench on a wheel nut and adjust it until it clicks the same time the wheel starts to rotate. This will give an approximate value due to the wheel nut not being on the centre of the drive shaft. Good enough for the backyard mechanic.

De-Ranged wrote:I have seen slippery housings where this has broken the centre housing and don't do it unless I'm specificity asked

I have seen numerous factory lsd (ie not shimmed) with broken centre housings. I imagine if they're weak enough to break then putting more strain on them is asking for trouble

wow , I have never heard that. The hilux diffs when used in 2wd drag and track cars tend to absorb 400hp before they let go.(according to a prominent diff shop in Auckland)
i wonder if the spinning wheels, and undulating terrain when used in a 4wd application puts more pressure on the diff than sheer horsepower?

Bigger tyres