My current truck is a '97 4WD Ram 3500 Dually, and I've been toying with the idea of putting a limited slip in the rear end. My previous truck was a 1/2 ton chevy with a semi floating 14 bolt and a gov-locker, and the thing I dislike most about the current truck is the fact that it has open differentials. I really don't want a detroit in something that is on the street 95% of the time I drive it, but I also don't want to spend too much money. I was hoping I could find a limited slip for $300-$400, but everything seems to be $600-$700, at least for a dana 80. The truck has a dana 80 with 3.55 gears. Anybody have any recommendations for a cheaper LSD or even a locker (other than a detroit...or a spool)? Would sourcing used parts be a good idea, or would you steer clear? Thanks!