I have a 75 2 door Buick Skylark that I am parting out. What rear end does it have and is it worth holding onto? Tom Suffolk,Va
Jack it off the ground and spin 1 wheel and the other spins the opposite way then it's most likely a posi.:Smarty:
i think you may have this backwards. Most if not all differentals will spin the opposte way i think you ment to say SAME direction as your turning. o No: is the drive shaft connected in the above mention?
It will not be a positive traction differential if when you jack it up and spin the passenger side tire, the driver's side barely spins or doesnt at all. Both will spin at the same rate in opposite direction if it is a positive traction differential.
1975 Skylark could have the 7.5 as well as the 8.5 10 bolt leaf spring rear differential. A quick check to tell if it has a limited slip (posi) carrier. After properly blocking the front tires carefully jack the diff. housing up on ONE side getting ONE rear tire off the ground. With the trans in NEUTRAL spin the wheel off the ground forward. If the wheel and driveshaft easily spin you have an open carrier diff. (or a really wasted posi) but if it won't turn or there is heavy resistance in turning the wheel (limited slip clutch pack breakaway torque) and driveshaft (providing the drum isn't sticking) then it may very well be a limited slip carrier. Sadly being that it is a gas crunch year vehicle it probably has a high gear with an open carrier but you never know so it doesn't hurt to look. Later...Tim PS: Jacking it up with BOTH wheels off the ground and the trans in NEUTRAL--BOTH wheels WILL turn in the SAME direction with a limited slip (posi) rear. An open will spin in the opposite direction with the trans in gear (park) and both wheels off the ground. It depends on how you are jacking the vehicle and where you put the resistance (tire or pinion yoke)
