hey mike, wlecome for the reply, just doin our part right, second did you mean 3.73 or 4.10 gears? those are the available gears for your truck. also the coil spacers i am talking about do not spread the coils, they go under the coil to push the whole thing up, mine are made from a high density polyethylene 3 or 3 1/4" outer diameter with a 3/4 or 1" hole in the center, i believe the stud is 3/4 but there is a nut down there so there needs to be a hollow or divit of some kind to cup the nut..... anyway i think superlift sells some that are 1/4" thick you just stack them. they don't affect ride quality cause they use the oem spring and don't spread the coils.
not to steal ray's thunder but, a detroit locker will definitely do wonders for your 2wd, yes it goes in the rear differential and provides equal traction to both wheels when the situation calls for it. it will unlock around corners so as not to make it unmanageable. good luck and have fun