Christian Dionne
Member
It doesn't improve economy, it's so the front end doesn't spin the propshaft when not in 4wd. Just think of all the reciprocating weight that is still turning even with the diff disconnected. Your AWD transfercase is always turning the propshaft, and your hubs are always turning the axles, so where is the economy going to come from??? In the 4wd trucks, the only thing not turning in 2wd is the propshaft, not much of a gain there.