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Author Topic:   mustang rearend gear question
ss27
Dirt Full Roller

Total posts: 47
posted August 26, 2005 12:52 PM  
What is the difference and how can you know the difference between the 7.5 and the 8.8 readend in a mustang?

Also will the gear interchange?

racerman707
Dirt Freak

Total posts: 374
posted August 26, 2005 05:09 PM  
The gears won't interchange. Do you mean tell the difference in how they look or how they run?

ss27
Dirt Full Roller

Total posts: 47
posted August 28, 2005 02:12 PM  
How they look to know what is in the car to be able to get some different gears.

racerman707
Dirt Freak

Total posts: 374
posted August 29, 2005 04:10 PM  
The 8.8 has a big square cover. Almost all 5.0 mustangs have 8.8's unless it's a mid '80s GT. They are 7.5 LSD. What model is your car?

ss27
Dirt Full Roller

Total posts: 47
posted August 29, 2005 06:39 PM  
around 1982, does the 8.8 have a pumkin like the 9in?


racerman707
Dirt Freak

Total posts: 374
posted August 30, 2005 06:22 AM  
No. The back cover comes off a 8.8. If yours looks like a 9 inch it is probably a 6.75. The 8.8 weighs about 30 pounds more than the 7.5. I would use a LSD 7.5 for better acceleration. A limited slip carrier will run around $150.

ss27
Dirt Full Roller

Total posts: 47
posted August 30, 2005 03:11 PM  
The back cover comes off of mine, I am just tring to find out what I have so I can change gear ratios.


HAFBREDSTANG
Dirt Roller

Total posts: 6
posted September 08, 2005 10:11 PM  
The easiest way to tell is pull the pinion yoke off and count the splines on the pinion shaft. The 7.5" has a 28 spline shaft and a 8.8" has a 30 spline shaft. You can do this without pulling it apart, more than likely you can do this without having to pull the yoke all the way off, take the pinion nut off you can see the splines good enough to count them. Hope this helps.

ss27
Dirt Full Roller

Total posts: 47
posted September 09, 2005 03:43 AM  
Thanks, for the info. I was told the axels are the same.

mini50mod4
Dirt Newbie

Total posts: 4
posted September 17, 2005 03:16 PM  
the covers are the best way to tell the difference between the two, if it has a carrage like a nine inch its either an eight or nine inch they are both front loaders, they didn't start putting 8.8s in the mustangs until mid 84 the gears will not iterchange between a 7.5 and an 8.8 but they has the same ratios

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