Rear Differential Noise:
I took the ST over to a mechanic friend's shop yesterday to get his opinion on my rear diff noise. He's pretty sure it's coming from the spider gears, but says you can't be 100% sure until the cover's off.
I looked into a spider gear set and found a pretty good price for a US Gear set at RockAuto for $117 and the forum's 5% discount will pay for the shipping. I also looked on eBay and found a complete used 8.8, 4:10, 31 spline, Posi center chunk for about the same money. I was thinking maybe that would be an easier way to go, but my friend said that he's never installed a used rear end from another housing and not had it roar. He believes that this is because of not being able to duplicate the torque on the carrier bearing caps to match whatever it came out of. I trust this guy's opinion. He thinks I'd be better off marking my carrier bolts, and using a torque wrench to figure out exactly how tight each of the carrier bolts are before removing them, then putting them back exactly where and how tight they were. I hope to have the time (and ambition) to pull the cover and center section this week. I'll go from there.
Update:
Pulled the diff cover and found a few things that didn't make me happy.
1. Fluid level was quite low. I didn't measure it, but I'd estimate about a quart came out. Probably due to axle seals leaking. Didn't look like it had water in the diff fluid, but read on.
2. There is evidence that there was moister in the diff, as some of the ring gear teeth were rusty. I'm not sure if this will require replacement of the ring & pinion. The pinion gear looks fine. The wear pattern looked ok. As only some of the teeth were rusty this truck must have sat in one place for quite a while.
3. I think my mechanic friend may be right about the spider gears. They don't look too healthy (very worn and some teeth were pitted). I'll run them over to his shop tomorrow and see what he says.
4. The limited slip clutches were quite worn out on the passenger side. The driver side clutches were not too bad, but they come as a set to do both sides. I still thinking on whether it's worth replacing the clutches. It should work fine as an open diff if they slip.
Question: Is there a trick to removing/inserting the "S" spring in the posi unit? I had quite a time getting it out and I'm not sure how to reinstall it. I've seen posi clutches replaced on Power Nation TV, but I don't recall how they did it. Maybe I can find a youtube video. - Never mind. I found a video.
I just came back from the mailbox and my used cruise control switches arrived. They look like brand new. I'm very happy with them and can't wait to get them installed (and yes I know the trick on disconnecting the old ones from the wiring harness).
Update:
Used cruise control switches installed. Neither side lights up, which is better than having one side light up. While I'd prefer they both illuminated, I seldom drive at night anymore.
New spider gear set ordered along with axle seals. There's supposed to be an O-ring on the axle shaft where the C-clip goes. Not sure why, but I'm missing one, so off to Ford to try to find one tomorrow. Also need some LSD additive while I'm there.