I have seen this sort of design before.

There is a large company in Australia that now makes similar lockers for the more mainstream models. By all accounts so far, very much stronger and without the "O" ring difficulties of the ARB's.


One design idea from this one would be to reverse the "blade" and "channel", so the "external selector ring" (diagram) sliding in and out of the differential hemisphere has the "blade" (making the design slimmer, allowing for more engagement from the sliding pins), and putting the "channel" on the screw in air actuator.

One other thing the do in their is to use an air actuator situated inside their diffs mounted to the bearing cap bolts. This avoids any "critical" alignment of the air actuators mounted through the third member.

Seen here seperated


and here mounted



The obvious advantage is it only needs a non critical hole to be drilled for the air line access.

If you need use an external air actuator would it be possible to provide (say) a 25 x 25 x100mm bar of steel that is drilled with an alignment hole in it to clamp and bolt to the third member hard up against the webs, using the bolt holes that join the third to the axle housing, to position the required hole? This would enable the local installer to get the alignment correct on the actuator access hole. This would also be considerably cheaper when shipping than trying to ship an entire third member.