I've ran a LR in my front D60 for years now with no issues. First couple of years was with 38's and now 40's. I've also broken several 30-spline stubs so I'm not easy on it. On the other hand my buddy did break the LR in the D60 on his truck, but this was also on a 7,000 lb., 42" tires, and a big-block after a couple of years of abuse. It did not grenade, just would not always lock up going forward but worked in reverse.
For the comment about the rear end locking up after 15 miles, I just really doubt that had anything to do with the lock-right. Unless you really messed up the install there is nothing in the LR that would make the axle lock up. More than likely the ring and pinion or bearings were the true culprit.