Them 4or5 Big trucks on 5tons they don't really need it. Then smaller trucks and stuff it definitely make a world of difference. My 81 has Detroit lockers front and back!!. When I drive it on the road the rear end will chirp
There's one break on the top of the front end and rear.. On most 2 1/2ton axles and bigger.. Not like a one ton.. Where all four tires have breaks.. I run 3/4 ton axles on my race truck..