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Discussion Starter · #1 ·
Hey guys,
I have a question about 9 in posi. I picked up a 59 ford 9in open rear and was able to locate another center section which is the same spline count. The guy says is a posi unit. I know from years ago when you have the car in the air if you turn the rear wheels both wheels should turn in the same direction if it's a posi. I know there's several didn't types of posi rears out there going by different names and also work differently. I don't know alot about these rears so I want to make sure I'm getting what I'm paying for. So, my question is this. If when the rear is in the air and you turn the axles and they don't turn in the same direction does this mean there's no way it's a posi. What if your turning the center section (where the drive shaft bolts) and someone holds either the left or right side axles and you can still turn it, does this mean its not a posi. As you can tell by my qestions this is what's happening whith the rear I have. So, to say the least I don't think it's a posi but I really not sure how to tell completely. Can someone help? :( :thumbup: :thumbdown:
 

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No matter what type of limited slip, posi, or whatever else you might call it, if you turn the yoke both wheels should spin the same direction. If someone holds one of the wheels and you turn the yoke the person holding the wheel should have a very difficult time keeping his wheel from spinning. For anything other than a locker or a spool, there will be some amount of differentiation allowed between the wheels, so a person could hold one of the wheels while you turn the yoke, but he would definitely feel the wheel trying to spin.
 

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Discussion Starter · #3 ·
Well,
The problem is when you turn the yoke and hold either axle you can still spin it. Both sides are the same.
 

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Most likely, it's an open (single track) differential, given what you've described.

However, a limited-Slip/Traction-Lok differential could act the same if the clutch discs have sufficient wear that they will no longer lock the axles together.

Only sure way to know what it is, is to pop it out and have a look-see.
 

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Before pulling the center out, just pull the drivers side axle and look at the splines. There would be a destinct line/stripe in the middle of the splines. The line only shows on limited slip rears because of the posi inards. Try that first.
 
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