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I have a 1970 f100 with a 460. I now have the truck in pieces its going to paint next week and the motor and trans are
getting done now.I need a new rear axle. The truck has a open diff and that cant fly with this truck. What would be a good swap? I am going to a junk yard this weekend to look for a interior so i hope to find something when i am there. Thanks in advance for all the help
In a Bumpside F100 with a 9-inch rear end, look on the door tag under the "Axle" heading. Any code listed there with two digits ("08", "09", "17") for example will have an open (single track) differential. All Bumpside Ford 9-inch rear ends came with 28-spline axles/differentials. --Only the '68-'72 F100s with a Ford 9-3/8" rear end came with 31-spline axles/differentials.
If there's an alpha-numeric under the axle heading, (example: A1, A2, B9), the 9-inch rear end will have a limited slip differential.
--this all assumes the door tag isn't missing, the drivers door has never been replaced or that no one has changed the 3rd member or the entire rear end assembly out on the potential donor truck.
Dentside trucks are more likely to have a Traction-Lok differential. They are also more likely to have a 31-spline differential/axles. Any 9-inch rear end axle code on a Dentside that starts with an "H" (H2, H4, etc.) will have a 4-pinion 31-spline Traction-Lok differential.
--You would need the 31-spline axles from a '68-'72 F100 9-3/8" rear end to be able to install a 31-spline 9-inch 3rd member in a Bumpside 9-inch rear end housing. --which is what I have under my '69 F100; '69 F100 9-inch rear end housing with '71 F100 9-3/8" 31-spline axles with a '75 F150 4x4 9-inch 3rd member with a 31-spline Traction-Lok differential.
If you want to build a good axle you already have the "bones" to do so. You can order up a new set of 31 spline axles and put a Powertrax diff in your existing carrier. This will probably be somewhere around $1000 in parts but then you'll know what you have.
If you want to build a good axle you already have the "bones" to do so. You can order up a new set of 31 spline axles and put a Powertrax diff in your existing carrier. This will probably be somewhere around $1000 in parts but then you'll know what you have.
If you know what you're looking for, you can get factory parts to beef up the rear end for considerably less.
This is a Ford 9-inch Daytona N-case 3rd member I picked up for $75.00 (in link below). It came from a '75 F150 4x4. The N-case is the ultimate 9-inch 3rd member for strength. It has a 31-spline 4-pinion Traction-Lok differential with 3.50 gears.
I got a pair of 31-spline axles from a '71 F100 that had a Ford 9-3/8" rear end. Both axles with shipping was $265.00, plus the $75.00 N-case equals a total of $340.00.
