OK guys heres the deal I just bought a 86 F250 4wd I knew the rear was bad when I bought it I think the rear has been replace before from some other truck heres the BOM 603381-5 and the tag says 3.73 in the first 3 numbers I asume that this means it's 3.73 gears. I pull the tag off the front and tryed to clean it up(rusted and pitted) but could only make out a .10 in the first three numbers so if i am right about the rear axle tag then the front would be a 4.10 so far i havent found the BOM on the front. could you help me with the rear BOM and if what i said about the tags are correct. B/C I need to know what rear ratio rear end to look for ( I dont think 4.10's and 3.73's would live happy together in 4wd)

 

you do know if you take those numbers to your nearest ford dealer and go to the parts dept they will be able to tell you exactly what it means, and for free. i have done every ford vehicle we have ever owned (thats a lot too, we have 7 vehicles right now, that i have done)

just a heads up

-cutts-

 

You are correct with the first assumption. BOM 603381-5 means open diff, 3.73 ratio. Based on the BOM, this axle is from a 73 - 74 F250.

There is a pic in my gallery of the Dana axle guide for 67-78 trucks that shows the BOM for this axle.

 

Thanks Alot 86rustbucket now I am going to look for the right rear end to put into my new toy

 

fishman heres a ? for you all i got is a sticker on the inside of my axel nothing on the outside of it