Outer Limits 4x4 Board

For anyone in the know, what is the strongest front diff option and locker for a 100 series 1999 live axle?

been running 36 x 12.5 pedes for a few years. rear locker used often....still havent managed to destroy front diff...not even some groaning noises.


wanting to get front locker in (probably a mc Namara) good time to get in good crown wheel and pinion and whatever else while everything is out.

anyone made it indestructable?

look forward to hearing something.

Look at the TJM ProLocker. It's a licence-built McNamara locker. I have them in my 105 series and they are nearly unbreakable! They have an actuator inside the diff that is seperate to the actual diff mechanicals, so it won't leak oil like an Airlocker and is easy to replace if it ever plays up.

Get rid of the factory crush spacer on the pinon and get a solid one machined up for it. This will help with strenght. It stops the pinion from "seperating" from the crown wheel especially in reverse. Did mine about three years ago and have not busted one yet. Has an ARB locker.

treebruiser wrote:Get rid of the factory crush spacer on the pinon and get a solid one machined up for it. This will help with strenght. It stops the pinion from "seperating" from the crown wheel especially in reverse. Did mine about three years ago and have not busted one yet. Has an ARB locker.

the pinion spacer does nothing for the strength of the diff. the ONLY advantage of a solid spacer is it gives the ability to change the pinion seal without worrying about getting the pinion bearing preload right. the locker is responsible for you increased strength. upgraded mounting studs from 8mm to 10mm will also stiffen the case, further adding to improved gear alignment under high loads.

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Thanks for everyone's input.

will take it all on board.

i am running the pro-locker in the back.....cant fault it yet.
will be having a chat with Total Traction soon...

anyone heard of an aftermarket crown and pinion that run more teeth and different pitch/angle? supposed to be stronger steel?


no rush on this but when i do it i want to be able to load the thing up in forwards or reverse and give it a boot full without thinking.....' i better go easy on it'

thanks again.

adam kenny wrote:anyone heard of an aftermarket crown and pinion that run more teeth and different pitch/angle? supposed to be stronger steel?
no rush on this but when i do it i want to be able to load the thing up in forwards or reverse and give it a boot full without thinking.....' i better go easy on it'

thanks again.

hypoid gears such as you have in your diff are naturally stronger in forward than reverse. in the "drive" direction, the pinion tends to pull into the crownwheel, forcing the teeth into mesh, within the limits of stiffness of the carrier and case. in the reverse direction, the pinion and crownwheel are forced apart, so are much more likely to fail, no matter how else you strenghten the assembly.

aftermarket gears tend to use the same tooth count (and therefore pitch) as the factory gears, to maintain identical drive ratios. there is arguably not much in it, strength wise, however if you buy cheap mexican gears, you get what you pay for.

with a landcruiser, the front diff is the 'weak' link when reversing uphill. upgrade the carrier and the mounting studs, then accep that it is the weak link, and don't put yourself into a situation where you have to drive backwards up a steep hill.