ID'ing a rearend

[19felix69]

just wondering what info can be obtained from the id tag on a 9". for instance, the rearend i pulled out of my '75 reads

WDM-A U 5DC
3 . 25 9 387B

3.25 must be the ratio... and thats all i know. any help?

[FORDification]

My Hollander's manual lists 'WDM-A' as belonging to a 9" rearend from a '63-'71 F100 with 3:25 gears, non-locking, and 28-spline axles.

I'm not sure what the 'U' is for.

The '5DC' is the date code ( 5= model year: 1965; B= month: April; and the C= week...so your rearend was born in the 3rd week of Apr. 1965).

As you surmised, the '3.25' is the gear ratio. (Just so you know for future reference, the '3.25' in the second line would have been '3L25' if it had been a locking rearend.)

The '9' shows it has a 9" ring gear.

The '387B' is the plant code...sorry, I don't have that info.

Hope this helps.

[NATHANHASNORIDE]

Just making sure i understand this keith. If the ratio is for example 3.25 like his then it is non-locking...and if it is like 3L00 then it is a 3.00 locking differential?Does this apply for all 9" rear ends?

Thanks!

[FORDification]

Yes it does...all locking-type differentials will have the 'L'.