I just bought an 09,FX4 and got under it tonight looking around and there isnt a tag on ther rear diff. So I checked the door tag and the axel code says "L6", and I cant find out what it is. I know the Fx-4 is spose to be 3.73 with an elctric locking diff but without the tag Im not sure they didnt just put fx badges on an xlt or something.

 

L6 is a locking 3.73. The locking is accomplished by pulling out the 4x4 selector switch (just like when you turn on the fogs). Can be done only in 4x4 and below 25mph. That assumes that someone hasn't modified the rear, as it normally will have a tag.

 

Yeah, I know how to lock it...I just cant figure out why there is no tag on the diff of a brand new truck? Im sure it has the locker because it has the switch on the 4x4 but why no tag, i guess I should contact the dealer.

 

Usually, if no tag, someone opened it up and did not replace it. Question would be, why was it opened up?

 

Yeah...the truck was brand new ordered in for me, unloaded off truck so I dont know. There isnt even any marks on the paint where the tag would have been. Im gonna have to investigate.