I have a 1958 f100. I am trying to figure out what kind of rear end is in my truck. I tried looking for any information on the differential but only was able to get dif 750. Does anyone know what this means. it has a side entrance to enter the oil on the right side. it has two dimples in the front. i can post pic if it helps out. thanks in advance.
if it still has the stock rear end in it,it should be the 9" rear end. very easy to identify a Ford 9" from any other rear end. do a google search as there are lots of sites out there with info on the 9" rear and how to identify one.
In 58 (like all 57 to 60 F100s) the common axle is the Ford 9". But, if the truck had a limited slip, it would be a Dana. A quick way to check is to stand behind the rear bumper, and look under the truck. On the Ford 9" you will not see any bolt heads on the center part of the axle (there will be nuts on the front). The Dana will have bolt heads on the back.
Here is the ford 9" rear end that is in my 60. You likely have the same rear end if it is original. The original gear ratio in the 57-60 9" rears was 3.7:1. You may find a little tag where the nuts are that says 3.7.