I have a 2003 F-150 with the 8.8 rearend. I have been smelling gear oil for the past couple of weeks now and after looking a few times for the leak, i finally found where it is coming from. It is leaking out from the center of the u-joint area, where it mounts to the pinion shaft....so it acually looks like the u-joint itself is leaking. Most pinion seals that is see leak are from the end of the diff. housing and the pinion shaft. Looking at it with a flash light, you can see the oil spot inside the u-joint area.....probably around the pinion nut.
Has anybody ever run across this before?
I am thinking about pulling the drive shaft off tomorrow. In the event the pinion nut is a little loose..Does anybody know what it should be torqued too?

 

yeah, My 00 is doing the same thing but I can't see oil on the surrounding area, It has to do with a sealent they put on the nut, I don't know any specs though and I am not to sure about how to do it, you can get a kit that has the new nut, crush bearing and some other doodads.

 

Mark the pinion and nut with a center punch, count the number of threads behind the nut. remove the nut. Remove the yoke, clean off the splines with brake clean, put a small amount of silicone in the splines. Install the yoke and reinstall the nut untill you have the same amount of threads behind the nut and your punch marks line back up. works like a charm.

 

Isn't there a crush sleeve in there that you have to replace?

 

Yeah...but my problem might be the pinion nut has already loosened. I understand about marking and counting threads and even taking a reading with an inch pound torque wrench.So the question is ... if the pinion nut is already loose, how do i come up with a baseline?

 

If you feel the pinion nut has come loose, then you will have to replace the crush sleeve.