When I bought my car, I was going to have the stock gears put in right away. Then the mechanic said the rear was a 7.5 and the gears I had wouldnt work. before I take his word for it 100%, I'd like to check for myself. It has posi and has apparantly held up to some abuse in the past.
How to identify 7.5" rear from the outside?
- Thread starter VadersV6
- Start date
8.5"
I was told that when you look at the 8.5" from the back the housing is squared off on the lower left and right sides. So you will see the normal cover for the 10 bolt but on a 7.5" you will just see where the cover bolts to the housing, on the 8.5" there will be an extra squared off part on both sides. Is this making scene? A 7.5" will look like this form the back: (_) where as an 8.5" will look more like this: [_]. Does that help? The 8.5" will have extra "ears" on the bottom. -Gabe
I was told that when you look at the 8.5" from the back the housing is squared off on the lower left and right sides. So you will see the normal cover for the 10 bolt but on a 7.5" you will just see where the cover bolts to the housing, on the 8.5" there will be an extra squared off part on both sides. Is this making scene? A 7.5" will look like this form the back: (_) where as an 8.5" will look more like this: [_]. Does that help? The 8.5" will have extra "ears" on the bottom. -Gabe
I found this site and now Im confused.
My rear has the 7.5 "ears", but it doesnt measure what the site says. The cover is pretty much 11 by 11"
rear end indentification
My rear has the 7.5 "ears", but it doesnt measure what the site says. The cover is pretty much 11 by 11"
rear end indentification
hum
The first page you posted had the gaskets at the bottom; I didn't know the 7.2" was the same as the 8.5". I know they measure the covers really weird. I've had this problem before. Do you have a local auto parts store that may have both gaskets on the shelf? Maybe looking at the gaskets in person would help. Also you could look for numbers on the rear end. I believe they were on the axle housing, driver’s side if I remember correctly, check both sides. If you find some numbers you could call the dealer and give them what you find, they should be able to help you. A different choice would be to call Randy's ring and pinion here on the west cost, they should be open and could probably help you figure it out. Hope this help... -Gabe
The first page you posted had the gaskets at the bottom; I didn't know the 7.2" was the same as the 8.5". I know they measure the covers really weird. I've had this problem before. Do you have a local auto parts store that may have both gaskets on the shelf? Maybe looking at the gaskets in person would help. Also you could look for numbers on the rear end. I believe they were on the axle housing, driver’s side if I remember correctly, check both sides. If you find some numbers you could call the dealer and give them what you find, they should be able to help you. A different choice would be to call Randy's ring and pinion here on the west cost, they should be open and could probably help you figure it out. Hope this help... -Gabe
Brent,
I have an '83 Malbu wagon with a 350 SBC & 7.5" rear end, and my GN has its original 8.5". If you send me a pic of what's under your car I can compare and tell you. One thing's for sure: the 7.5" looks a bit less "beefy".
EDIT: Never mind, I pulled your email from your profile and sent you two pics.
HTH,
Morgan
I have an '83 Malbu wagon with a 350 SBC & 7.5" rear end, and my GN has its original 8.5". If you send me a pic of what's under your car I can compare and tell you. One thing's for sure: the 7.5" looks a bit less "beefy".
EDIT: Never mind, I pulled your email from your profile and sent you two pics.
HTH,
Morgan
Thanks guys. Morgan- you have mail. My drive to work is going to be a lot farther now, so I need the right gears really bad now. I figured Id just have Lou C throw in the right rear for me with the right gears. I have 4.11's now and am going to a stock GN rear with 3.42's.
Post a picture or email me at pier1122@bellsouth.net and I can tell you.
HTH..
The 8.5 has squared "ears" at each lower corner. The 7.5" has "fangs" at each lower corner.
HTH..
The 8.5 has squared "ears" at each lower corner. The 7.5" has "fangs" at each lower corner.
I know this is an old post but this should help people with this question in the future. http://tech.oldsgmail.com/axle_ident.html
