My 76 shop manual is not showing me the correct axle code. Anybody out there with the 78 id info book.. the axle code is 13J on the door tag.

 

2.75 Open axle (non-locking)

J stands for power steering.

Have a look at this page of mine.

http://www.clubfte.com/users/mil1ion...ruckCodes.html

 

Thank you Mil1ion

 

The axle tag is the most reliable means of checking ratio. If it's been changed, it is unlikely anyone replaced the original tag, cause it's too much like work lol!

If no tag, you can do the tire spin test. Work for me everytime.
Mark