i have a ford nine inch out of i believe a 61-72 f100. Its 61 or 61 1/4 wide (measured from outside of axle flange to outside of axle flange). Its a 28 spline right now and im hoping to convert it to 31 spline. According to number dummies info 31 splines in this year were always in a special rear with a 9 3/8 ring gear, which isnt something i want to deal with. Sticking with this housing (28 spline at the moment) Can i use the 31 spline axles out of the goofy 9 3/8, pop them into my housing and have a new 31 spline carrier installed. Basically i want to put 31 spline axles and a REGULAR 31 spline carrier (detroit truetrac) into a 67-72 housing. thanks i have a ford nine inch out of i believe a 67-72 f100. Its 61 or 61 1/4 wide (measured from outside of axle flange to outside of axle flange). Its a 28 spline right now and im hoping to convert it to 31 spline. According to number dummies info 31 splines in this year were always in a special rear with a 9 3/8 ring gear, which isnt something i want to deal with. Sticking with this housing (28 spline at the moment) Can i use the 31 spline axles out of the goofy 9 3/8, pop them into my housing and have a new 31 spline carrier installed. Basically i want to put 31 spline axles and a REGULAR 31 spline carrier (detroit truetrac) into a 67-72 housing. thanks

 

Order 31 spline axles in the same length as the stock axles. or use the "goofy" 31 spline stock axles as they are the same length and backspace as the 28 spline.

The 9 3/8 ring gear fits in the basic same case with the same dimensions. The housing if it came with a 9" needs a slight notch to clear the ring gear on the way in to the housing.

ND sometimes scares the hell out of persons with this part number this and that.

I have a 9 3/8 28 spline case with 2.75 gears on a 66 housing in my 64.

Garbz

 

awesome thanks! Not trying to say anything is wrong with the 9 3/8 rear, i just want to buy a eaton posi and they only make them for a true 9. basically i bought the rear end today, its a 28 spline from a 1967 pickup (i think). Im planning on buying 31 spline axles used and dropping in a eaton detroit truetrac. Does anyone know how to read the axle tag? Its hard to read but i think it says WDH-K all i know is w means diff. then it says 3. 70 for the gears 7ED made in 1967 i think. And then 302 which i think is the plant.
so it reads

WDH-K
3 70 7ED 302

can anyone (number dummy) verify what this means?