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Discussion Starter #1 (Edited)
94 LX with the original open 3.08 in it.. so yea, I'm wanting something a little spicier than that. My thinking right now is to just see if I can find gears and an posi unit to replace the existing ones. From what I'm eyeing at the moment, it'll be considerably cheaper than buying a new pumpkin. I doubt I'll try this myself as there's the small window for error on clearances and other things related to install.. but I have someone than can load them in for me.

Also, I'm thinking of going to 3.55s instead of all the way to 3.73s. It's a small difference, but it's enough to make a difference. Anything wrong with my reasoning here? It's something I'm rolling around in my head right now.. no definite plans yet but that could change real quick.

Edit:\\ oh,forgot to ask.. what tooth speedo gear would I have to swap to?
 

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According to my FRPP catalog, you need the Orange 20 tooh gear

There's nothing wrong with 3.55's, a gear swap is something you don't want to do a lot. So if you're going to spend the money, might as well go overboard and get 3.73's. So if later you want more, you've already got it.

You can find a nice used mustang GT 8.8 Trac-Lok carrier off ebay, find one with low miles and have it installed in to your existing pumpkin. Along with the Ring & Pinion of your choice (3.55, 3.73)
 

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Green95LX said:
You can find a nice used mustang GT 8.8 Trac-Lok carrier off ebay, find one with low miles and have it installed in to your existing pumpkin. Along with the Ring & Pinion of your choice (3.55, 3.73)
If you go used, you will need one out of a 96-98 Cobra or another Tbird. A regular pumpkin out of a Mustang won't work. Our cars have an Independant Rear Suspension (IRS). The side gears are machined to fit IRS half-shafts instead of solid axle shafts. You can buy a Mustang pumpkin and have it machined, but the cost is the same as buying the correct one to begin with.
 

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Discussion Starter #4

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Do a search on the IRS vs. solid axle differential. This has been discussed in detail and never put to rest. :leftright

"No! They won't work!"
"Yes! They will work!"
"You can get the correct side gears from Dan!"
"Blah, blah, blah!!"
"Etc..... " :thumbsup:

I'm not going to jump into that snake pit again. :D

(Although the only IRS Cobra differential that has the 28 pline is the 99 Cobra, the laters have 31 spline. Someone correct me if I'm wrong as I'm pulling this off the top of my head. :D )
 

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no a live axle will not work, pn was orginally e9sz4026b , replaced by 2l5z4026aa , the new number is a 02 up explorer
 

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Discussion Starter #7

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It works, and it's been done my multiple people. I wouldn't have suggested it if i didn't know it worked. I personally talked to Rich about it and witnessed his car driving, so it does work. The so called "bevel" is only cut into the side gears of an IRS vehicles to help get the halfshafts out without taking the rear cover off. You'll be fine with a low mileage GT Trac-Loc unit, and i would sugggest that since it is the budget way to go.
 

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my information was according to the ford catalog, but thats not to say they cases and internals arent the same, yes they do list the seprate side gears.
 

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It really will work though, no matter what the FRPP catalog says. any 28 spline carrier will work.
 

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not frpp catalog actual ford parts catalog, but thats ok
 

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94 Daily Driven 4.6L said:
(Although the only IRS Cobra differential that has the 28 pline is the 99 Cobra, the laters have 31 spline. Someone correct me if I'm wrong as I'm pulling this off the top of my head. :D )
Whoops...got my wires crossed. You're right. ONLY the 99 Cobra rear will work. The 96-98s have a solid axle, and the 2001 and up have a 31 spline. Sorry for the confusion. :zbash:
 

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Just to clairify, A solid axle carrier doesn't disqualify it from working in an 8.8 IRS Housing.
 
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