Hi,
Same as a SWB, same as S2. But brakes may be different size, wheel studs may be smaller on early S2, all interchangable.
Unless of course, you want the HEAVY DUTY Salisbury axle (can't remove diff as a unit). VERY HEAVY, and not too common, but brakes are much wider ..... possibly 3" wide shoes.
Note, you cannot interchange SWB/LWB REAR axles, as the LWB springs are mounted on chassis outriggers. Can be converted if you can weld. Early S2 LWB used same diff as front axle, interchangable but be aware of the filler plug. Later S2 LWB and all S3 LWB used heavy duty axle on rear. Repeat - very heavy. S2 LWB can be fitted to S3 LWB, and vice-versa, but you need the matching prop.
602