Help, what is my rearend? 67 F100

[divadavidcars]

I have a 67 F-100, 3.25 gear with a broken ring gear. I have not taken it apart yet, any idea how many teeth would be on it? I dont want to take apart yet to see until i have it. Any help?

[spartman]

You would have a ring gear count of 39 and a pinion count of 12.

[FORDification]

An F100 should have a 9" rearend. Shouldn't be too much trouble finding a replacement center section at the local junkyard...just be sure you get one from a bumpside truck to make sure the axle spline count is the same. Our trucks have a '28-spline axle, as do some cars. Other cars and '73-up trucks have a 31-spline axle.

[REDNECKMOBILE]

An F100 should have a 9" rearend. Shouldn't be too much trouble finding a replacement center section at the local junkyard...just be sure you get one from a bumpside truck to make sure the axle spline count is the same. Our trucks have a '28-spline axle, as do some cars. Other cars and '73-up trucks have a 31-spline axle.

If you go to the junk yard and find a late model 31 spline chunk you can also get the 31 spline axles to go with it and replace the 28 spline axles at the same time to make it work.

[averagef250]

Some bumpsides got 31 spline axles as well. If it's the 5000 GVW 1/2 ton it got the big bearing 9" with 31 spliners. You will need to get yourself an axle shrinking machine if you try to stuff dentside 31 spline axles into a bumpside. Dentside axles are about 3" longer. I do believe you can get axleshafts from older trucks though. Not sure how far back they used the same width rear axle.

[67highboy]

I didn't think the axle shafts were interchangeable because the bumps had a shorter axle in the back