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I'm looking to buy a 93 F250 from a friend. I am curious what gear ratio it has. It is a 351 with a 5 speed. The "Trans" and "Axle" code on the door jamb read "W" and "39" respectively. Can anyone verify that this is the ZF transmission for sure and what the axle gear ratio is from these codes? If not, where can I go on the net to find this Information? Thanks.
I'm surprised at the 1991 model year you found for the "39" axle. I know for a fact this truck is a 93 model and it's never had the axle changed out - I guess the axle was just made in 91 and left over to be put on this 93 model truck? Anyway, where did you find this type information? I hate to see that it is an open diff - I sure was hoping for a limited slip or locker type. Seems that there is a post on the Superduty forum that deciphers these codes for the newer Superduty's but I can't find such a post on these 90's models. Seems that on the newer Superdutys that all axle codes with just numbers like my "39" are open and if there is a letter in the axle code it has a locking mechanism. Is this true of these older trucks also? Thanks SoCal.
Look in the 'tech articles' section of the site (upper right hand corner box, the bottom choice on that row of text). On the tech articles page, way down near the end, in the 1998 articles section, is the link to the axle code info. I think the '91 code applies to year '91 and later, at least that seemed to make sense to me. You're right, limited slip axles have a letter in front of the number. As far as I know, Ford only put TracLok, wich is actually a limited slip, in them, no real lockers. I put a LockRight in the back of mine .