BobC,
I've had experience with
Lock right (good for the money, kind of sloppy/jerky on the street with the same character or actually worse than the older Detroit with popping/banging let-goes. The cross shaft is a weakness. You must get the extra hardened cross shaft. Oversteers in turns under power and understeers when you let up. You get used to it and adjust.)
Detroit (the newest incarnation works great. Minimum noise, almost transparent, bullet proof. A good choice on any surface)
ARB (I have a pair on my CJ8's D44/D60's and they are the Cadillac of lockers because of the on-off feature. My air lines leak a little bit (it is called the AIR LEAKER you know), forcing the compressor to cycle on every 1/4 hr. or so while wheeling. I don't think this has any relation to the 5 roll overs suffered by my Jeep? HMMM? HMMMM? 8<)
I've never had any other problems with them, but have heard and seen people with bad 'o' rings and pulled or fried air lines. You really do get 4 wheels turning the same speed while in use. Only electric, OX, spool and Lincoln lockers can claim this.)
Trac-Loc (the most common limited-slip around. Transparent on slippery surfaces. The poorest performer; slips too quickly; not much help. Maybe O.K. for glare ice. Expensive to rebuild. Only last 60-70K street miles before rebuild. Don't even think about this one.)
Power Lok (the best, IMHO, of the limited slips. The amount of grip (preload) on the cone clutches is adjustable by adding more cones. I like it especially on the front axle on slippery surfaces. Had one on my CJ8 for years and never had trouble. In fact I attribute the "just slip at the last minute" for me never breaking a front D30, even as much as I beat it up on The Hammers, Rubicon, Ershim, etc. for years. It was like a fuse slipping just before the D30's torque resistance was reached. My friend Mark has an ARB on his front D30 and he's broken maybe 10 front axles, mostly at the outer U-joints)
The Ford 9" is a good axle choice, especially if not used much on the rocks. I say this because the pinion position is one of the lowest exits on the pig making it more vulnerable than almost any other axle because it hangs so low. Get one off a Lincoln Continental or Big Ford car. Be sure to get a 35 spline. I think it would be fine in NY with 4.10 (if you have a 1:1 high gear, 4.56 or 4.88 if you have overdrive and 33-35's) and a Detroit even on ice and snow. If you're concerned about driveability woes, go with a pair of Power-Loks. forgiving/transparent on the street.
regards, as always, jefe