My 02 F150 Supercrew has a couple of issues with the rear diff. It has about 130K miles on it now.

Right now, both rear axle seals are leaking and need to be changed. They were done a couple of years back and about 25K miles ago. Anyone know if there is a revised seal available? Does not seem like something I should need to do this often.

Secondly, the rear end makes an odd noise once it has been driven on the highway long enough to get good and warmed up. It will only do it on sharp turns at low speed then. It has been suggested to me that I need to change the clutch pack in the diff.

Has anyone done it? Any write up about it - hopefully with some photos?

Randy

 

The noise sounds like the LS locking up slightly you actually need to add some friction modifier and if the seals are leaking you would indeed be low on it. I assume the noise is groaning sound.

 

Yes, the noise is mostly a groaning sound. It only does it once it gets good and warmed up. If I come in from a run on the highway, it will groan when I turn corners in the city, especially tighter corners at low speed - or at least that is when I hear it.

I am running full synthetic diff oil and a bottle of the smelly friction modifier stuff obtained from the parts counter at the local Ford dealer. If you have not used it - be aware - it smells awful. The parts guy warned me when he handed over the bottle and he was right.

I have talked to a couple of people who have suggested the clutch pack needs to be redone. I hear the parts are not too bad but labour could be a bit so I thought I might tackle it myself. I need to do the seals anyway right now as it is leaking quite badly on the passenger side. Just started or at least just got bad enough for me to notice on this past weekend. So long as I have to drain and pull the axles, I thought it would be a good time to address the clutch pack too. Was hoping someone on here had done it and could offer advice.

Randy

 

is it a 8.8 or a 9.75

 

Don't know. How do I tell the difference?

Randy

 

axel tag. this is that tag off redwood's truck with a 3.55 limited slip 9.75 axel. the bottom line is what you want. the 3L55 is limited slip 3.55 and the 9.75 is the axel.

 

Crawled under to check for the axle tag today. Not easy as I had the truck undercoated and the tag got sprayed. Scraped enough off to read it and it is 3L55975 etc so the limited slip and 9.75 inch.

Randy