My truck is a 2007.5 I need to replace my rear and want to get one from the junk yard. How can you determine if the truck your getting it from has the locking rear? Is there information in the vin#?

Check the RPO codes in the glove box. That's the easiest to get to. Not sure if the axle will have a tag on it or not. If you're still not sure, popping the cover off will tell you for sure. I would highly recommend doing this for any axle that you buy from a junk yard. In many cases, the axle may have been pulled from the truck already. This is the most reliable method to make sure the axle is in good shape and has the proper ratio.

What happened to your present axle?

Jake

I was hot dogging it doing whole shots. Reving up to 1700 rpm and letting go of the brake. It must have twisted something in the diff (thats my and my mechanic opinion) and the rear axel seal is leaking fluid where the axil and and hub bolt together. You can see it on the wheel. Does this sound probably to you ?

Whoa, you changing rear axles because a seal is leaking.
I know some where you thought something was bent. It is not hard to inspect whats on there.

Rear of the truck in the air, tranny in park, place a reference marker near the tire/ rim and have a helper spin the other tire while you check (watch) for "wobble".

Now, remove the tire, and unbolt the 8 axle stub bolts and set aside.
Slide out the axle.
Read through this to see the better seal. http://www.dieselplace.com/forum/showthread.php?t=372697&highlight=axle+seal

And this for the basic how to. http://www.dieselplace.com/forum/showthread.php?t=84927&highlight=axle+seal


And the two seals to put it all together again http://www.dieselplace.com/forum/showthread.php?t=335927&highlight=socket+seal including the socket, which requires minor modification.

the mechanic showed me the axle and you can see the teeth are kinda waivy but still within spec. The mechanic was sayin somethin was twisted between the axle and diff because where the axle and wheel bolt up they don't mount flush. I will check into the links. I was thinking of hitting the junk yard and pulling a complete rear out of an 08. They should all be the same with the G80 diff as long as the gear ration is the 373 (which is what I have) right?

I find it hard to believe you really hurt that axle, i do not care how hard you were beating on it. The only rear axles i have heard of being seriously damaged were the guys doing serious pulling "truck pulls". Yes the G-80 will come apart but other than that i cannot see you hurting this axle.

I have seen guys in my wheeling club burn 44" boggers on bare ledge and bounce the rig right off the ground with the old 14bolts. IMO our axles are superior in strength to the old 14bolt.

The teeth on the axle are definitely wavy. I guess thats what happens when you rev it up and and let her rip with those 35" bfg's they just grip rip.

Couldn't you just change the offending axle stub?

dropped it off at another mechanic that works on my buddy's hot rod. Says he is really good so i'm curious what his opinion will be.

Sounds like a twisted axle. Don't let anyone tell you this don't happen. I have a set to show them

What does your "twisted" part look like?
http://www.fordmuscle.com/pics/Silverliner_31%20Twisted%20Splines%20Comp.JPG

Many times, just the stub axle can be replaced.

Found the problem. The shaft the inner bearing rides on is 100ths of an inch to small from the factory. This is allowing the race of the bearing to spin on the shaft and over time leaks gear fluid.
The fix: Locktite 660 around the innerside of the bearing to the shaft to keep it from spinning. Only time will tell if this fixes the problem. If this does not fix it was thinking of hitting the junk yard and getting an etire rear.
Any thoughts?