7.5 or 8.8 rear end?

R

Rdrcr

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#1

• Nov 6, 2007

• #1

My quick search did not help me find an answer. Is there any way to verify if my '86 GT has a 7.5 or 8.8 rear end without taking it apart? I would like to get some 3.55 gears installed this weekend and want to be sure that the correct parts are ordered.

Mike

 

NIKwoaC

中國製造

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#2

• Nov 6, 2007

• #2

an 86 GT should have an 8.8 unless someone for some godforsaken reason swapped in a 7.5

you can also check the axle tag, VIN, etc

 

R

Rdrcr

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#3

• Nov 6, 2007

• #3

^^^^
Is there a digit in the vin # or rear end that will tell me? It was my understanding that my car should have the 8.8, but I would hate to tear things apart only to find that my assumption was wrong.

Mike

 

samickguy15

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Nov 6, 2007

#4

• Nov 6, 2007

• #4

Check the door tag. That should have an axle code. There should also be a tag on one of the cover bolts on the axle. It will read something like 2L73 8 8 or 3 55 7 5, etc. First series of digits is gear ratio, second set is ring gear diameter. Also, the 8.8 has 4 flat edges on the cover while the 7.5 has two visually.

 

R

Rdrcr

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#5

• Nov 6, 2007

• #5

^^^^
Very cool, I'll check it out.

Thanks

Mike

 

85_SS_302_Coupe

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#6

• Nov 6, 2007

• #6

Sorry i'm a bit late on this one. You can identify it by looking at the bolt pattern on the diff cover.


EVERYONE right click/save as:

7.5:

8.8:

As you can see, the 7.5 is sort of oval shaped while the 8.8 is more of a rounded square kind of shape. Note that they have the same number of bolts too so that doesn't give any hints. Hope that helps.

 

PUNISHER RACING

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#7

• Nov 6, 2007

• #7

EVERYONE right click/save as....................That kills me you know it happened to!

 

Roland69

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Sep 17, 2005

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#8

• Nov 6, 2007

• #8

cant you measure from the top to botom

 

SuperStang83

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#9

• Nov 7, 2007

• #9

They came stock with 8.8

 

bloopbloob

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#10

• Nov 7, 2007

• #10

why measure? just listen to 85_SS_302_coupe! if you look at them, the difference is obvious immediately!!! a 7.5 will have 2 flat sides.

 

SVT32VDOHC

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#11

• Nov 7, 2007

• #11

The 8.8 will have quad shocks on it, and the 7.5 won't.

 

R

Rdrcr

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Thousand Oaks, CA.

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#12

• Nov 7, 2007

• #12

Yep, thanks guys. 8.8!

Mike

 

85_SS_302_Coupe

it sucks (I know) to be on the receiving end

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#13

• Nov 7, 2007

• #13

SVT32VDOHC said:

The 8.8 will have quad shocks on it, and the 7.5 won't.

Click to expand...

True...some of them had "slapper bars" but i have no idea what years had them. I literally have 0 experience with a 7.5 aside from the 7.5 pumpin in the IRS on my Merkur.

 

SuperStang83

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#14

• Nov 7, 2007

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Thanks for the handy diagram 85!

 

SVT32VDOHC

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#15

• Nov 8, 2007

• #15

The 7.5" can be built up, but why bother? You can always weld the quad shock brackets on the axle housing of the 7.5 I guess.

 

85_SS_302_Coupe

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#16

• Nov 8, 2007

• #16

SVT32VDOHC said:

The 7.5" can be built up, but why bother? You can always weld the quad shock brackets on the axle housing of the 7.5 I guess.

Click to expand...

Yeah, back in the day it was all about a 7.5 with a Detroit locker in it, unless you had the cash for a 9 inch. Now you can build up an 8.8 to be just as strong or stronger than any 9 inch.

 

jspagna1

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Nov 8, 2007

#17

• Nov 8, 2007

• #17

85_SS_302_Coupe said:

Yeah, back in the day it was all about a 7.5 with a Detroit locker in it, unless you had the cash for a 9 inch. Now you can build up an 8.8 to be just as strong or stronger than any 9 inch.

Click to expand...

Yes, the 8.8 will be cheaper than a 9" and is very strong. You could compare it to GM's 12 Bolt Posi rearend.