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Old Aug 8, 2008 | 03:17 AM
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Third member swap question

Can you swap in a third member from any year, provided of course the spline count is the same? I am hoping to go to the junkyard and find a lower geared replacement and just need to know if I can look at the 80's model trucks also.

I currently have 2.75 gears in my 77 f150 2WD and recently shoved 33's under it so I"m looking to lower the ratio a bit.

Thanks for any info
 
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Old Aug 8, 2008 | 10:26 AM
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Yep, pretty much! That is the handy part of them, not sure when Ford went to the 8.8", maybe those were in the rangers only, but the 9" are plentiful. Easy to pull also.
how about this,,,,
http://fresno.craigslist.org/pts/787785988.html
 

Last edited by Pickupmanx2; Aug 8, 2008 at 10:47 AM. Reason: found some info
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Old Aug 8, 2008 | 11:23 AM
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8.8 statred in the 80s. I just swapped a 77 9inch into an 85 I figured it was easier to just do the whole thing rather than the third member. The only thing was the yokes were different and the brake lines on the 80s ones were metric.
 
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Old Aug 8, 2008 | 12:14 PM
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As far as a 9" and 8.8 goes im 99% sure theyre all the same. The Dana's may be different tho
 
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Old Aug 8, 2008 | 12:24 PM
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No 8.8 has a cover in the rear and a 9 inch dont. It also doesnt have a third member like the 9 inch its more like a dana rear. The 8.8 does not have a third member it has a carrier with the ring gear on it. A nine inch has the yoke, pinion and carrier all in one package that is what a third member is. They are two different beasts every 2wd ive had from the 80s has had a 8.8 and the 4x4 I have has the 9 inch.
 
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Old Aug 8, 2008 | 10:20 PM
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3rd member/ pumpkin... close enough to the same thing if you ask me, but to each thier own... i was merely stating that all gears should interchange with an 8.8... and all gears for a 9" should interchange. Center section or no
 
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Old Aug 8, 2008 | 11:04 PM
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There are some 9's that are actually 9 3/8s, and those don't fit in the same housings. Buy carefully. But, yes, same spline, good to go.
 
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Old Aug 8, 2008 | 11:42 PM
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Originally Posted by 85e150six4mtod
There are some 9's that are actually 9 3/8s, and those don't fit in the same housings. Buy carefully. But, yes, same spline, good to go.
Very good info, I got a 31 spline posi for free with the same gear ratio as my truck so I figured I'd just stick the posi member into my housing, I stuck it in there alright, about half way... after spending an hour or so getting the ring gear unstuck from my housing I went to look at the housind the posi came out of, it was originally under a bronco, it had been clearanced with a grinder, thats what I did to mine also, problem solved, works real well. would be interesting to know what that posi was in originally...

EDIT: Tracloc for all you purists...
 
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Old Aug 12, 2008 | 03:22 AM
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Originally Posted by straightsix4x4
Very good info, I got a 31 spline posi for free with the same gear ratio as my truck so I figured I'd just stick the posi member into my housing, I stuck it in there alright, about half way... after spending an hour or so getting the ring gear unstuck from my housing I went to look at the housind the posi came out of, it was originally under a bronco, it had been clearanced with a grinder, thats what I did to mine also, problem solved, works real well. would be interesting to know what that posi was in originally...

EDIT: Tracloc for all you purists...

It probably came out of a Lincoln car. They had the 9 and 3/8's.

I have several 9" rear ends and pumpkins. Some from cars some from trucks.

You mainly need to make sure if it is 28 or 31 spline axles. I have rebuilt many of them through the years. I liked the Detroit lockers the best for racing dirt track, street machines, and drag racing. Now I am 67 years old and not racing anymore, but building two trucks right now with the 9 inch rears. Both will be posi, (trac loc), and one has the stock 389 gears in the "N" pumpkin that it came with in a 75 chassis, 4x4. I don't know if it has 31 or 28 spline, but guessing it is 31 spline. I also have a couple other posi's, one will go into the street rod pickup that has an open 2:75 9" right now. It too will have the "N" case but 4:11 gears, and 28 spline axles, in a Mustang rearend.

Another good strong pumpkin is the older "war" pumpkins used in some of the 57-59 Fords, I believe, maybe some later ones. Has the extra ribs, but no "N" on it. I just have one of those at this time, hard to find.

Jim
###
 
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