8.8, 9.75, or 10.25 Rear diff?
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8.8, 9.75, or 10.25 Rear diff?
What's the easiest way to determine which rear differential my 2001 Supercrew has? Bought it used and I guess I never looked into it. The qty of friction modifier changes from 4oz to 8oz depending on the size....
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There should be two metal tags attached to the axle cover bolts on the rear of the axle. One of those tags will have a plant code (usualy starting with a v or a s)that tells you which plant it came out of, a four or five digit number[year(#)|month(letter)|day(#)], a 3 didgit number(axle ratio)[example 3 .08 or 3 .55], and a ring gear diameter # which will be two digits(for example 8.8). If your looking at the right tag, the axle ratio will be on the bottom left of the tag, and dirrectely to the right of that will be the size.
Most axles are like this and if yours isnt let me know and i can find out how to identify it.
John
99 f-150 4x4 ext. cab(84k)
rear steel buper..grilleguard w/4 KC lights
tool box..bed linner
dual exaust..K&N air intake...<!-- / message --><!-- / message --><!-- / message --><!-- / message --><!-- / message -->
Most axles are like this and if yours isnt let me know and i can find out how to identify it.
John
99 f-150 4x4 ext. cab(84k)
rear steel buper..grilleguard w/4 KC lights
tool box..bed linner
dual exaust..K&N air intake...<!-- / message --><!-- / message --><!-- / message --><!-- / message --><!-- / message -->
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Joined: May 2004
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From: DFW, TX
there is another number and maybe letter under the bolt head. The short answer is yes, you have a 9.75 (you probably also have a 5.4L engine). The number and possible letter that is under the bolt head should be a 3. So if it reads 3 55 9 75 OK31, then you have a 3.55 gear and a 9.75 open rear end. if its 3L55 9 75 OK31, then you have a 3.55 gear and a 9.75 limited slip rear end. Also, you can look at the sticker on the driver's door jamb and get the axle code. You can figure out what it means here https://www.ford-trucks.com/article/...r_Decoder.html
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Rob88
1980 - 1986 Bullnose F100, F150 & Larger F-Series Trucks
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Mar 28, 2000 11:15 AM
