Thread: Diff locks

Maxi's/ARB's/Jac Mac's are all manually operated lockers.

That is they lock when they're selected, via a switch.

ARB's and Jac Mac's are air operated. ARB has a solenoid. Not sure how JMac does it.

The Maxi Drive is vacuum operated, via a pneumatic type switch. Takes vacuum from the engine. Has a reservoir as well.

Detroits are different. They're always locked until they need to disengage (on corners etc) They make both lockers and LSD's (Tru-Trac's).

Generally speaking it's always a good idea to upgrade the axles when fitting a locker.

Maxi Drive lockers come with axles. They dont work with standard axle(s).

The others are just a locker, no axles.

one other thing to consider if you decide to go the detroit or LSD option as opposed to the selectable difflock

Detroits do not lock in reverse and neither do some LSD's...

not a bad thing untill you need to do a stall recovery on a knarly bit of track.

Are you sure that Detroits don't lock in reverse? Thats the first time I've heard this.

You can get maxi axles with the arb lockers. It's what I have.

Isn't it some free wheeling hubs that don't work in reverse?

Detroit lockers do lock in reverse, well mine does anyway.
In fact you can reverse them when you pull the diff down and double their life span.

Hi Jeff
The major benefit of a manual locker over an automatic locker is on a greasy sideslope,that automatic locker locks and you will spin around!!!
Andrew

the one I pulled down was locked only when travelling forwards..

I dont get to see much detroit drive line stuff, but I get to deal with their engines on a regular basis..

As best I can describe it...


a normal open diff with a pair of one way sprag clutches on the carrier to the axles.

when you corner the outside wheel is driven faster than the carrier and the sprag clutch allows this.

when a wheel slows down in relation to the carrier the sprags bite and drive the axle.

when you drive the carrier in the opposite direction it doesnt work as the sprags are working the wrong way and if a wheel looses traction it speeds up and its sprag will grab. the one that is stationary will continue to slip its sprag as the relative motion is the same as if it was the wheel that was going faster while going forwards.

I'm not sure that thats totally correct but I'm fairly certain that its the same principale as to why cone slip LSD's dont all work in reverse and its along the lines of its being driven the wrong way. (much like reversing the direction you turn a nut winds it off the bolt instead of on).