So I was hearing some funny sounds coming from my rear diff on my 02 FX4 pulled the cover off and found 4 or so bolt heads have sheared off inside. This is way beyond my mechanical abilities to rebuild.

Have any ideas how this could happen beside me being a terrible truck owner and not changing the fluid enough?

What do you guys think:
Have my mechanic rebuild it?
Can anyone take a wild guess at how much that will cost just so I dont get ripped off.

Should I replace the whole axle?
What axles are compatible with my truck?

https://drive.google.com/folderview?...zQ&usp=sharing
This is a torson limited slip

 

wow...how many miles did it have on it? was the oil low? i bought my '88 @ 100K miles and it was 5 years old, diff oil hadnt been changed and didnt have any issues...heck nothing had been changed, original trans oil too! had the original starter/alternator at 200K also....some pictures would help, id just swap out the whole rear end, get a 2010/2011 axle so you get factory disc brakes...just check the tags so you get the same gear ratio...
..on edit: saw the link for pictures after i responded. looks like you have a 4.10 limited slip, and the bolts broken are the ring gear to carrier bolts, never seen that happen...they are hardened bolts, so even though its not too big a deal to pull the carrier/ring gear, it would be a bitch to drill/extract those...id almost suspect that someone was in there before and things didnt get tightened up, some bolts backed off and hit other solid parts in there. (like the bearing cap?) i dont know how else that could have happened....

 

Yeah id go whole new axle they can be had for around $300 and doesn't require a whole lot of mechanical know how to swap them. Id start checking local yards!

 

Never seen that before. Diffs don't usually fail like that. Makes me think someone swapped gears and didn't torque the ring gear bolts down properly. Or reused the old bolts (supposed to use new ones).

If I were you I'd swap out with a used axle because it's probably the cheapest and easiest way to do it. Just make sure you get one with the same gear ratio (if you're 4x4). Look around for axle swaps, there's quite a few write-ups as its a pretty common mod

 

Thanks for the replies
Gotta new axle coming with only 80k on it. It was way over $300 but I guess that's cause of the limited slip. Know anyone interested in a free axle to rebuild.

 

...if you werent so far from me, id take the axle, but ca is a long ways from oh....shipping would be more than i could get a good axle for.

 

Lol 02 fx4...it's probably a Torsen LS unit, they tend to grenade. pos


Edit just saw the pics. Makes sense why that happened, almost all of the Torsen units in that year fx4 blow up and cause problems, nothing out of the ordinary but if you got another 02 axle with the same LS, replace it with a ford racing one or an actual locker

 

As far as I know 02 was the only year they had that problem. I would try to find an 03+ level II axle. The torsen limited slip IMO is far better than a standard clutch type limited slip.