I've never had the two side by side, so I don't know directly, just going off of what PPFJ60 said.
With a FF rear axle however, can't the axle shafts handle more torque before snapping because they are not supporting the weight of the vehicle?
In the weight range we are talking a bout in a 60, not really. You basicaly have to bind the axle shaft against the wheel bearings before the FF SF strength differences come into play.
If you have 7,000 lbs on the rear axle, yeppers..
Extreme 4x4 did a custom axle set out of 14 bolt units, custom d60 outers bla bla bla.....
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to East Coast Gear Supply for getting an order and shipping it in 20 minutes.