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Discussion Starter · #1 ·
This is an aluminum housing, independent rear suspension Ford 8.8" differential (complete center section). Believed to be out of a Lincoln Mark VII, which would make it a 1984-1992 (if the Mark VII origin is accurate...not positive on this).

The tag reads:

430B
3 07 88 3C23

The unit accepts 28 spline axles.

My GUESS is that it was manufactured 3/7/88 and that it has a 3:23 gear. I'd bet that the "C" between the "3" and the "23" indicates whether it's limited slip or not. Since I'm just guessing, can anyone help?

I need to know the gear ratio, is it limited-slip or not, and will any aftermarket limited slip units Eaton, Auburn Pro, etc.) work in these Lincoln 8.8" units?

I don't have this unit in my possession, so I can't do the usual manual checks to discover this info.

Thanks in advance!
 

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Well I'm fairly sure that any 8.8 inch differential will fit in this as I believe that almost all 8.8s have the same basic specs. the auburn unit should fit as well as a detriot locker and ford trac loc for an 8.8. I've got an 8.8 in my 86 F150 4X4 that I put a detroit ezy locker in.(done professionally that is)
 

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Discussion Starter · #3 ·
Correction on the info in my original post: I learned from someone who works on Lincolns frequently that since the unit is aluminum, it has to be from a Mark VIII, NOT a Mark VII. That makes it 1993 vintage or newer.

I still need to know the gear ratio and type of differential (open or limited slip), if anyone can decode the tag. Thanks!
 

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It is 3.07 gear, open, 8.8" (it would say 3L07 if it were limited slip)

Only Mark 8's and new cobra IRS's get the aluminum center section. Same thing as 89-97 tbirds and cougars. Only the super coupes and xr7's got the 8.8 though, base models got 7.5" irs.
Mark 7 was fox chassis, making it a solid axle.
Becuase of the snap rings that hold the axles in the carrier you can't use a normal 8.8" diff to replace although the irs diff will replace a solid axle diff. I don't know off hand of any particular aftermarket ls/locker available that will accept the snap rings.

oh and uhh.. I happen to have a low milage center section here that is LS.. out of a 90 super coupe(same exact thing, but not aluminum). 2.73 though.

<font size=-1>[ This Message was edited by: ummduh on 5/1/02 4:14am ]</font>
 

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Discussion Starter · #5 ·
Hey, ummduh, thanks a lot for the info!!

I'm still just a bit confused:

You stated: "It is 3.07 gear, open, 8.8" (it would say 3L07 if it were limited slip)"

Here's where I get confused. The tag on the unit in question reads like this, with the spacing just as I have typed it below:

3 07 88 3C23

According to your decoding method above, where 3L07 would be a 3:07 ratio, then wouldn't the tag on the one I'm looking at which reads, 3C23 be a 3:23 ratio?

I think it's confusing that the series of numbers starts with the "3 07" but there is a space between the 3 and the 07. What do you think?

A fellow who does a lot of work on Mark VIIIs advised me that (in his opinion) on these vehicles some 3.07 ratios were open and some limited slip; but that all 3:23 ratios were limited slip. However, I have heard that the "L" in the last series of numbers does stand for limited slip, just as you indicated. I wonder what the "C" stands for in this one? C clip style axles? "Closed" versus open diff?" Any opinion on that? I don't have a clue!
 

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Re: Need help decoding tag on Lincoln 8.8" IRS differential

I also have a IRS that I am installing into my 50 Ford f1 Truck. The IRS came outta 94 Lincoln Mark 8. Has 8.8 Diff. Im pulling out a 9" which hooks up to my C4.

The Mark 8 has a 4R70W trans and had an aluminum Drive shaft.

My issue is how to couple my C4/drive line to that 8.8 te flange is different

Has any one done this? I have the aluminum Drive line from the donor car too.

thanks
Fittyfod
 
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