yeah mine whines most in 5th but if you rev out 4th pretty far you can get it to whine as well.
i dont know anyone who has a tracker or a samurai that doesnt say “man i beat the living piss out of that vehicle and it just takes it” 
as far as i know, mine still has the original clutch at it at 147k. i know both the previous owners and they said that they never replaced it and it went to the 2nd owner at 63k and he never replaced it. it still barks second and it barked 3rd this spring once on a hard shift.
so im guessing the rear end will be fine for a while.
Brian