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Axle sizes, options, and widths

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199K views 231 replies 192 participants last post by  barobertolittlea6367  
#1 · (Edited)
Ok so I am in search of a junkyard upgrade for my Foxbody 28 spline 7.5. I see no point in upgrading to an 8.8 unless I also go 31 spline. The stock Focus rear suspension appears to be around 61.75" WMS to WMS from what I can tell. Which is wider than I had originally thought.

So I wanted to compile a list of vehicles, options, and widths. This is what I have.

83-92 Ranger - 28 spline, 7.5 and 8.8, 56.5"
93-09 Ranger - 28 spline, 7.5 and 8.8, 58.5"
FX4 Ranger - 31 spline, 8.8, 58.5"
91+ Explorer - 31 spline, 8.8, 59.5"
79-93 Mustang - 28 spline, 7.5 and 8.8, 57"
94-98 Mustang - 28 spline, 7.5 and 8.8, 58.5"
99+ Mustang - 59.875"
>05 Crown Vic - 28 spline, 8.8, 65.5" (or 62.5", conflicting info)
05+ Crown Vic - 31 spline, 8.8, 65.5"


Explorer 31 spline axle shaft lengths - 30.5" Driver, 27.625" Passenger (or 30.625" and 27.75", I am getting different info)
Ranger 31 spline - 30.25" and 27.25"
79-93 Mustang 8.8 - 29 3/16"
1994-1998 8.8 - 29 31/32"
1999-2004 8.8 - 30 11/16"
87-88 Turbo Coupe 8.8 - 30"
93 Cobra 8.8 - 30"
87-92 Lincoln Mark VII 8.8 - 30.5"

31 spline bearing size - 1.622 in. bore, 2.576 in. o.d., 1.550 in. width
28 spline bearing size - 1.399 in. bore, 2.295 in. o.d., 1.211 in. width


Please post more info if you have it. Cougar, Thunderbird, Mark series, Towncar, Continental.....
 
#2 ·
As of right now, it appears that my best bet is to pull a Mark 7 8.8 (since I believe it is setup with a 4 link like the Mustang) and swap in 2 driver's side Explorer axles. But based on the axle shaft lengths, that would put the total width near 62.5"
 
#4 ·
disciplerocks said:
As of right now, it appears that my best bet is to pull a Mark 7 8.8 (since I believe it is setup with a 4 link like the Mustang)
Click to expand...
It is. All fox body platform vehicles from the 80's had the same suspension setup and most parts are swap-able.

disciplerocks said:
Ok found more info that says the Mark VII rear is 1.25" wider per side than the Foxbody. Which would put the total width at 59.5".

Back to the googles
Click to expand...
Correct again, I had an 87 t-bird that came factory with a 7.5 rear and I swapped in a junkyard mustang 8.8 and gained about 1" more wheel clearance on each side.

The 83-88 birds and cougars are virtually the same as a mark 7

Don't even try to look under a bird or cougar for an rear, all 83-88 models came with a 7.5, even the turbo coupes, only the mark 7 got an 8.8

Ford always puts the better stuff into the lincolns, the birds with a 5.0 v-8 got a 150 hp and batch fired injectors like the crown vic did where as the mk 7 got the 225 hp sequential injected 5.0 out of the mustang. Hence the reason for the better rear on the marks.
 
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#3 ·
Ok found more info that says the Mark VII rear is 1.25" wider per side than the Foxbody. Which would put the total width at 59.5".

Back to the googles
 
#6 ·
I found another source saying they are 30.5". Looks like I will be doing some test fitting while in the yard.
 
#8 ·
Maybe you missed it, but I'm not upgrading unless I go 31 spline. So I need to find an 8.8 axle that is the right width, and find 31 spline shafts that will fit.
 
#9 ·
Haha. No big deal. That guy hasn't gotten back to me. And yes this is going in the Focus.

So it needs to be near the 61.75" Focus width, 8.8, 31 spline, and setup with the stock 4 link


I did start the thread to compile info for anyone looking for an axle swap as well.
 
#10 ·
#11 ·
If you decide to upgrade to 31 spline, you can get a 31 spline carrier out of any 97-2010 F 150 with a v-6 or 4.6 v-8 and all v-8 powered mustangs from 2005-up got 31 splines. The 5.4 trucks got the bigger 9.75 axle and in 2011 the 5.0, 6.2 and ecoboost trucks all got the 9.75. The 3.7 v-6 may still have the 8.8 but I don't know for sure.

Also on the 150's the door sticker with the axle code, a two number code indicates an open diff and a letter number code indicates a trac-loc.
 
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#12 ·
My plan is still to grab a Mark VII housing, and use 2 driver's side Explorer shafts, Explorer carrier, and probably the Mark VII brakes.
 
#13 · (Edited)
#14 ·
So my venture today didn't end with an axle in my truck. I grabbed 2 driver side Explorer shafts, and an 01 8.8 diff cover. Then went looking for a housing. The only 8.8 4 link housings were in Crown Vics and Towncars. Without being certain that the housing is the same size, I wasn't going to pull one. I will just wait until another Mark VII or Mustang comes in.

Although I did try to install the 31 spline shafts into a Towncar axle. They wouldn't fit. Do you have to replace the outer axle seal to fit 31 spline shafts?

And here is the 8.8 cover from Tbirds and SC. Not as cool as the Explorer.


Here is my Explorer cover.
 
#15 ·
Found this on TRS
adsm08 said:
31 spline shafts are bigger around, and 31 spline bearings are as well. The 31 spline bearings don't fit 28 spline housings and the 31 spline axles don't fit 28 spline bearings.

The 28 spline 8.8 far more closely resembles a 7.5 with an oversized ring gear than it does a 31 spline 8.8.
Click to expand...
 
#16 ·
I actually didn't look at the year of the truck, just based it on the style of the one in the link you posted.
 
#17 ·
Dustin, you can probably take a measurement of the od and id of the axle tube and the 31 spline shaft, and get a couple bearings and seals for it. I cant remember the name (tri state bearings?) But there is a place in Evansville that you can get it, and not overly priced either...

SVT
 
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#19 ·
I could the mounting brackets on and run a 6 link lol.



Good idea. Guess I will rent a bearing puller and grab on of each so I can shop around.

white89gt said:
I even like the aluminum covers that came on some of the Lincolns and Crown Vics.
Click to expand...
The regular ones that look the same as steel, just made of aluminum? I can get those all day.
 
#20 ·
#21 ·
#22 ·
The MN-12 platform t-birds and cougars and MK 8's from 89-97 used 5x4.25 or 5x108mm, and the taurus/sable twins up to 2007 used the same, the rebadged 500 they called the taurus in 08 had 5x4.5 or 113mm. Also the mk3 focus from 2012 and up uses the same pattern along with the new escape 2013-up and the new fusion and MKZ. You can get up to 19" wheels from a 13-up escape, fusion ,or mkz. 18's from a focus.
 
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#24 ·
That's what I meant, I should have been more clear in my post. You proably thought i meant the focus uses 5x114, after rereading my previous post, I can see how I was misunderstood.

Oh and in case you did not know, 5x 4.25" and 5x108mm is the same thing. Just like the bigger mustang pattern is 5x4.5" or 5x114.3mm
 
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#26 ·
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