I understand that the ring and pinion are a different ratio, but are the spider gears the same in both diffs? I was hoping they are and I can use the spare ones to weld up and still have the lower ratio of the lj gears (just assuming lower is better for less stress on engine, xfer case tranny, etc. ...

Is there any difference between the jl80 and sj410 differentials? I want to weld the rear diff in my lj80 and I have a spare axles from a 410. I'm hoping they are the same so I can just weld up my spare diff and swap it in. Also can I upgrade my lj80 front alxe with the freewheeling hubs on the 410 ...