novice question
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novice question
I'm guessing this one will be easy for ya'll. I see rear differentials refered to as 9", 8 3/4", etc. What is this a dimension of? Is it the diameter of the ring gear? And if so, how does one know what theirs is without looking inside?
Mine is a Ford 3300 Traction-Lok 3.70. That's all I know.
Another old ignorant guy.
Mine is a Ford 3300 Traction-Lok 3.70. That's all I know.
Another old ignorant guy.
Posting Guru
Joined: Jan 2006
Posts: 1,101
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From: Malvern, Ohio
well for example 8.8 or 12 bolt GM are Integral style rear axles which means you have to take the Ring gear/case out of the axle housing then the drive pinion gear. These axles have a cover you bolt to the axle housing the seals the "pumpkin" or whatever you want to call it. The axles are held in by c-clips on these types also. You can identify most axles by the shape of the pumpkin bolt pattern.
As for the 9 inch and 8 inch rear axles you take the Ring gear/ case drive pinion as one unit which is known as a Removable Carrier. The 8 inch has a smooth dome with 2 dimples and the axles are held in by 4 bolts. The 9 inch is the same except bigger and axles are also held in by 4 bolts. 9 inch dome has a hump in it to fit the 9 inch ring gear.
8 inche axles were meant for smaller lighter vehicles. The 9 inch was used in a very wide variety from big lincolns to truck to mustangs from differant widths also. The 9 inch production was stopped in I think 1985 or 1986 then came the 8.8 to replace it.
All or most (don't know exactly) non Heavy truck axles are semi-floating so 3/4 ton trucks and lower are semi- floating. Spicer axles have a rubber plug, Dana axles have a steel square plug in the differential.
As for the Ring gear size I am pretty sure that would be the diameter of the ring but Im could be wrong some how. I do know some traction lock rear ends do have a smaller backlash specification though like instead of .008 - .015 it could be .008 - .013.
Some 9 inch rears either have 28 splines on the axles or 31. Well thats all I know, there might be more but i dont know Im only 21 so I have lot of learning to do.
As for the 9 inch and 8 inch rear axles you take the Ring gear/ case drive pinion as one unit which is known as a Removable Carrier. The 8 inch has a smooth dome with 2 dimples and the axles are held in by 4 bolts. The 9 inch is the same except bigger and axles are also held in by 4 bolts. 9 inch dome has a hump in it to fit the 9 inch ring gear.
8 inche axles were meant for smaller lighter vehicles. The 9 inch was used in a very wide variety from big lincolns to truck to mustangs from differant widths also. The 9 inch production was stopped in I think 1985 or 1986 then came the 8.8 to replace it.
All or most (don't know exactly) non Heavy truck axles are semi-floating so 3/4 ton trucks and lower are semi- floating. Spicer axles have a rubber plug, Dana axles have a steel square plug in the differential.
As for the Ring gear size I am pretty sure that would be the diameter of the ring but Im could be wrong some how. I do know some traction lock rear ends do have a smaller backlash specification though like instead of .008 - .015 it could be .008 - .013.
Some 9 inch rears either have 28 splines on the axles or 31. Well thats all I know, there might be more but i dont know Im only 21 so I have lot of learning to do.
Last edited by 385seriesHemi; Dec 28, 2006 at 05:52 PM.
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Joined: Jan 2006
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From: Malvern, Ohio
No problem, I forgot, for calculating ratios you divide the Ring gear teeth by the Drive pinion teeth. So example 41 Divided by 10 you get a 4.10 ratio.
And for front wheel axles the Ring gear is reverse cut im pretty sure so you can't really get them mixed up.
And for front wheel axles the Ring gear is reverse cut im pretty sure so you can't really get them mixed up.
