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Hello,

I was just reading articles on the Ford 8" Open Axle when I came across an article on how to make a "Home Made" 8" Posi from an 8" Open.

Basically he says remove the rear carrier and within all the internal gearing there is a washer on each side of the gear, add an extra washer to each side (total of 2 on eah side instead of one) and this will push the gears together enough to create a posi rear-end that works well.

Here is part of the article.......

Lifting out the side gears you will notice that between it's thrust face and the differential case counter bore is a thrust washer, Ford part number C9OZ-4228-A it measures .031 thick. The function of this washer is two fold, it is a hardened surface between the axle gear and differential case to prevent metal galling and, it spaces the axle gears at the proper engagement depth to rotate the pinion gears. By installing two thrust washers on each axle gear instead of one, the gears are moved inboard enough to cause the pinion gear pitch diameters to bind, effectively locking up the differential assembly.

This modification still has the ability of slipping some on turns, but will have a ratchet feel similar to a Detroit locker. The washer trick works equally well on both 8" and 9" rears. I have done several of these for street and strip cars and I believe you will find the results rewarding.


This sounds to easy (and inexpensive) to be true. Has anyone ever tried this? Any comments?

Thanks, Greg.
 
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The parts, not intended for this application, will wear rapidly putting nice shavings in your diff. It might work for while, but it will either wear enough to be ineffective or fail some other component.

I believe this has been discussed before and the consensus was it was not worth doing.

If you go so far as to remove your diff, you may as well put good parts in it.
 

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Or you could just weld the spiders solid. Thats a real cheap way to do it, although turning will be challenging. When your rear end blows apart though, don't blame me!
 

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Consider your 350 money well spent. Putting a meshing gear into a bind condition is never good. Like Mr. Mike said... Fill your pan up with shaving. You never get something for nothing.
 

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I read the same article on a fairlane site. Seems like it may make a lot of noise on turns but I'll be trying it out pretty soon. I'll let you know how it works!
Don't ever let anyone discourage you from and idea!
 

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Try it first on a junk third member where the gears don't matter to you (if they get ruined from debris)....

Get back to us with the results...

When I used to street race, if there was a track race or big street race coming up, I had a set of 4.62's set up in an extra third member and used a mini-spool (cost 28.00).....worked fine, although it barked the tires on turns (I learned not to turn sharp). I use a similar unit (in a 9") in the race car....never had a bit of trouble with it and the tires don't bark as much because the rear end is narrower

Have fun!
 
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