I have a 2000 F-150 supercab 4x4 4.6l auto w/ 75,000 miles. I had to replace the rear U-joints an noticed a black film around the pinion flange but I didn't really think anything of it because there was no oil residue on the diff or the box, when I poped the driveshaft off the pinion flange a considerable amount of gear oil gooped out from the center of the flange. My question is how hard is it to change the pinion seal what the preload torque is supposed to be set at, and any pointers to make it easier. Another Question that I should ask is how do I tell which axle I have, the auto parts store siad my truck could have a 8.8", 9.75", or a 10.75"(I think that those were the numbers that he told me, the 10.75 seems big for a 1/2 ton)
Thanks for your help
Nick

 

If you have to ask, it is probably above you can do.

you have to pull the yoke/flange, pull the axles/carrier, change the crush sleeve and seal, and tighten the flange/yoke (with a new pinion nut and lock tight) nut slowly, checking the in/lbs it takes to spin the pinion. I believe 8-12 in/lbs is the amount with used bearing, but I am not 100% sure..

I think you have an 8.8" axle, that is what they normally put behind 4.6s. Also, 8.8s are notorious for having the pinion nut back off, which is probaby why you are seeing the gear oil coming from the middle of the flange.

10.5" rear came under most 7700 models of F150s. All 5.4s have 9.75"s (that I know of).

You could just tighten the pinion nut down tighter, but it'll eat your pinion bearings in the long run (and probably back off again anyways).

good luck

 

We have a service station at the feed mill were I work, comes complete with all the tools and the right tool to guide me along(mechanic hehehe). I'll probably do it on friday
thanks

 

Could be the oil is coming up the splines and out behind the nut.
If so it could just be loose or need some sealer.
If it was the seal it would come out between the housing (seal) and the flange.

 

yeah it seemed to be just by the nut, the oil pooled up where the hole in the flange is and when I took the driveshaft off it ploped out then

 

Then the cure would be to have the nut removed and sealed with sealer or replace the nut. Those nuts have a factory sealer on them.
You don't need a seal unless you just want one while they are there.