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7-5/8 or 8.5" ring gear?

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Old 01-16-2012, 02:38 PM
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so im in need of a axle shaft for my 99 jimmy with a 2005 GU6 G80 rearend, anyone know what size the ring gear would be on it? do the 8.5s only come on ZR2 models?

a friend sent me this link
New Page 1

i didnt take a tape measure to my cover but it does have the pointed ears on the bottom of the housing just like GMs 7.5 and 7.625 rear ends

my rear end


safe to say its the 7-5/8ths?
 

Last edited by swartlkk; 01-16-2012 at 04:17 PM. Reason: *Combining Consecutive Posts* - Please use the edit function to add additional information in your post if another member has yet to respond.
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Old 01-16-2012, 04:34 PM
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You have the 8.5 ring gear in that axle,I believe as that rear cover shot is identical to my GU6 without the limited slip! I have actually never seen a Blazer/Jimmy w/o the 8.5 gear! Ever! Just my input-step66
 
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Old 01-16-2012, 04:37 PM
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There are FAR more 7.625" rear s-series trucks than 8.5". The 8.5" was only offered in the ZR2 (all of them) and a few 5-spd 4wd 2dr models (but not all). Everything else got the 7.625" rear.

step66, it is likely that you have only seen Blazer's with the 7.625 and not the 8.5.
 
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Old 01-17-2012, 04:12 PM
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thanks swartlkk

every junkyard in my city refuses to sell me a axle shaft, they only sell the entire housing complete but i found 1 just outside my city that im gonna grab tomorrow afterwork! got a 2hr round trip to get this stupid thing lol
 
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Old 01-17-2012, 05:16 PM
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If that's the case in the rear is it safe for me to assume the front is the same?
 
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Old 01-17-2012, 05:22 PM
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Hey swartlkk! You may be right! Just my experience with a 96 & 97 with the tow package and a GU6 has always been 8.5 ring! At least in the units I have owned. Sorry if I spoke out of line...step66
 
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Old 01-21-2012, 11:13 PM
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Originally Posted by swartlkk
There are FAR more 7.625" rear s-series trucks than 8.5". The 8.5" was only offered in the ZR2 (all of them) and a few 5-spd 4wd 2dr models (but not all). Everything else got the 7.625" rear.

step66, it is likely that you have only seen Blazer's with the 7.625 and not the 8.5.
I have a 2003 two door five speed. I just did and oil service on it and it has the round cover 8.5" ring gear. from what you say above does that mean I have the wide stance diff for the rear, or does that apply only to the front diff being wider? How much oil dose the 8.5" use?
 
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Old 01-22-2012, 04:27 PM
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This is interesting as I spent some time in a salvage yard in DE yesterday-virtually all GU6 tow axles there had the 8.5 ring! Why do authorities make statements about the 7.625
when it doesn't seem to be true? Every Jimmy I have ever owned with the tow package had the 8.5! My experience only open to suggestions!
 
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Old 01-22-2012, 06:32 PM
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you will need about 2 quarts of oil to fill the rear dif... I filled mine by the book with 1 quart drove around for awhile and found weeks later it was too low. I needed just shy of a 2nd bottle.
 
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