Please enlighten me about the differance between a spool or a posi unit. Seems like a spool is cheaper?

hey a posi- traction carrier allows one wheel to spin, then when that one starts to spin it transfers power to the other ,letting both spin, this way it can take a corner as inside tire does not have to rotate as much as outer tire. a spool however links both axles together, thus giving both axles power at all times, making a turn very hard on your rear end, inside tire will chirp as it is skidding in turn, these are full drag race only, some use on street but go thru axles like you read about
jake

Thanks BB
are all older 12 bolts 30 spline axles?

paperman, i am not sure about spline count but i am pretty sure they are all the same i don't think they had any different , goodluck
jake