Technical 9" "Posi" Donor

Hey guys!!!! I have been looking for a ford 9" "posi" (ya I know, POSI is a GM term). I know of a good old junkyard back home with lots of different fords. I know I will have to raise the car up and check but what cars or trucks would most likely have a limited slip, so I don't have to jack up every car out there. Thanks!!!!

 

Mostly they came in cars that you're not likely to find in a wrecking yard these days.... but look for a late 70s Bronco or other 4x4 truck, or a high performance car like a mustang with a big engine.

this list will get you started...but it doesn't show which ones are likely to be ordered that way.

http://www.fordification.com/tech/rearends_ford01.htm

 

Also check high-optioned 'big' cars (mid/late 60s-early 70s), although you won't find the most desirable ratios in those....

4X4 trucks will be your best shot.

 

odds are the clutches will be so worn out unless it has a tag stating is posi you wont be able to tell...

 

Every decent sized swap meet I go to has at least a couple of guys selling 9" Ford third members and almost always a "posi" or two. Usually $250 to $350, often 31 spline from a pickup.

Considering it may be necessary to replace bearings, rebuild the limited slip, etc., I tend to think buying a new unit is more cost effective, especially if your current gears are the ratio you want and are in good shape. Something to think about, anyway.

Ray

 

A lot of the mid-70's full size Broncos or F-150's also came with the heavier duty "N" case carrier.
Got mine from a 78 Bronco, had the 4 pinion trac-loc , 3.55 gear, 31 spline n case for a $100.

 

Yea, if you are just spinning axles at the junkyard you might be missing some worn "posi" differentials. One general "quick look" without even crawling under to check the tag (if it is even present) is to look at the axle code on the warrantee tag. Usually, if the code is a letter or in multiple digits includes a letter the original axle is a limited slip. To be absolutely sure you should look up the code on the particular vehicle, here are a couple of charts for examples, one a mid 80s truck chart and the other typical of early 70s cars. .

 

x2.
My track-lock-equipped 9" rearend came from under an '81 F-150.

 

if you are lucky enough to find a tag on one of the 3rd member bolts, a locker will have an "L" between the numbers. ie: 3 L 73 indicates 3.73 ratio, locker

 

I don't think the L really means "locker", as in Detroit Locker. More like "limited slip", or "trac-loc".

 

Hey great stuff guys! If pickups are my best bet then I might be in luck cause the are LOTS of ford pickups out there and my car has 31 spline axles. One question though, where is this "warrenty tag"? Is it in the glove box?

 

Usually located on the drivers door or door jamb area.