BTM - Timing

[It\'s a Dry Heat]

How far before you need lockup do you btm?
Does both axels lock or just one of them?
How fast does it engage and disengage?

I know I've been around the forum for almost a year with my H2 and only heard parts of these answers. You guys are quiet down here. Thank you for your time answering.

The reason I'm asking is my daughter a Marine is not tought the trick. maybe military humvees don't have it. There trucks are in the 1994-96 models, They look it too. When they went to Irac there trucks went over on ship, my datghter with the trucks. Then brought the same trucks back. Thats while other marines are moving there trucks back and forth. Thanks again!