Locking a diff is good when you want to go in a straight line, need power to both wheels at all times, or want to slide. Otherwise you should probably leave it alone or add some really heavy fluid.
ORIGINAL: drevil
BTW Has anyone noticed that when you use an apostrophe in RCU it adds a second one right next to it which makes it look like you used quotation marks by mistake. For a few days I thought it was my keyboard doing this but then I noticed others having the same problem.
Its being taken care of.