I'm sure this question has been asked and answered many times but, are normal 10 and 11 gear pinions interchangable in the same rear end?
Gary
Yes, the ring gear has 40 teeth so the 11 tooth is the standard 3.63 to 1 and the 10 tooth is 4 to 1.
Rick
Thanks Rick
Like most things T, there is more than one answer. As you see below, before Ford offered them, there were aftermarket 10 tooth pinions that required their own special ring gear. The Ford special 10 tooth pinion was innovative in gear technology. It allowed you to replace the 11 tooth with a 10 tooth without adjusting the ring gear location.