I have a couple questions, hopefully there are some answers out there

To give a little background, I noticed some slop between the driveshaft and the wheels - freeplay with the transmission in neutral and the truck sitting on the ground. I checked the fluid level, and could see that the ring gear moved along with the driveshaft, putting the slop in the differential or axle splines. The pinion seal also leaked a little when the truck sat for a long period of time, but the fluid level was always OK when I checked. The pinion seal started to drip more often and after sitting only over night, so I decided to pull the rear cover and have a look.

After pulling the cover, I found the spider gears and side gears were badly worn and pitted on the contact surfaces, the lock-pin for the cross shaft was sheared at the base of the threads, one of the spider gear thrust washers was broken at the ID bevel, right side axle splines were badly worn, and right side axle was pitted at the wheel bearing. The ring and pinion look fine best I can tell.

Now for my questions: What would be the most durable and cost effective repair? Should I get a new LS differential from Ford (or Ford racing performance parts), or go with a used LS carrier with new clutches for ~$150. The axle shop I talked with said there was a good chance the carrier would be junk due to the sheared lock-pin and suggested the used carrier with new clutches instead of just replacing spider and side gears and clutches in the carrier I have. Would there be any reason to replace the ring and pinion if they both look OK? Should I have the axle shop do the replacement and setup the gearset or is it something I could handle? I have the factory service manual and I'm very mechanically inclined.

What is your preference for replacement parts source (diff, clutches, axles, R&P if required)? OEM? NAPA? Something else? The original axle was used and abused by my teenage self and was trouble-free for 190000 miles, and probably would have gone farther, but I wanted to catch any issue before it left me stranded on the side of the road or destroyed the housing. I'd like the replacement stuff to last that long too.

Thanks in advance, sorry for the long post, and I look forward to your replies.

 

190k? I'd think it was just about broken in.

You know these trucks about as well as any of us do, so a lot of the questions you're asking are really personal preference. Maybe you're just thinking out loud. I do that a lot too.

If it were my truck, this is what I'd do. I'd get a factory Ford trac-lok axle from the junkyard, add a powertrax no-slip to it (optional, but no clutches to wear out), an 8.8 rebuild kit, and a new ring & pinion. Don't cheap out. Ford parts are expensive because they aren't cheap chinese junk. Get some quality aftermarket parts like Yukon or Ford racing and build the axle in your garage. Buy online. When you're done building, swap it out. Swapping an axle isn't hard but doing the gears takes a while. I've never done it, but your aptitude level with this stuff is pretty high. I'd feel comfortable tacking it if I were you. You'll need a few special tools but it's not rocket science.

There's a guy on ebay that sells a Ford 8.8" rebuild video. It would probably be worth it. There are also a number of online guides on rebuilding c-clip axles.

Reusing the R&P is totally a judgment call. If they're in good shape, go for it. Personally, I would replace but I have a tendency to over-engineer things. Only an experienced pro can look at the gears and tell you if they're junk when guys like you & me think they're fine to re-use. Remember that gears have a memory of sorts and if you don't set them up exactly the same way they could easily fail a short time down the road. From a reliability perspective it would be worth it for me.

Also don't discount the idea of swapping in a 9". The RABS sucks anyway so it's not like you're losing anything really useful. The 9" is considerably stronger and the cool factor is a lot higher.

 

Andym has just about said it all. However, if it was me, I would contact Randy`s Ring and Pinion at ringpinion.com and ask their advice and also get any parts from them.

 

Andy you and I are thinking a lot alike. I would love to just slap some parts in it and be good to go, but I just have a hard time doing something half-way - I want it fixed the right way. Getting the old ring and pinion setup the same as before makes me more nervous than setting up a new set. Is there any preference OEM vs. aftermarket for parts?

I have been looking on craigslist for sometime now for an axle, but the closest I've come is a 3.08 open that's probably in a similar condition to the one I have. Luckily I have a second vehicle I can use in the meantime, but nothing can replace having a truck.

I did think about going to a 9", but I just had a new driveshaft made after swapping in the ZF, so I really don't want to have to re-do that anytime soon. I have no idea how similar the pinion location is between the 8.8 and 9. Along those same lines, what about finding a late model 8.8 with disc brakes? I could source the brakes and the replacement LS carrier to use as a donor for rebuilding my original axle. I don't want to open another can of worms and have to replace master cylinder, etc. to make the discs function properly. I think the easiest and quickest solution to get me back on the road is to just stick with the 8.8 with drum brakes and rebuild what I have, unless someone can convince me otherwise .

Lazy K, thanks for the suggestion, I'll give Randy's R&P a call and bounce some of these thoughts off of them too and see what they can suggest.

 

I would be surprised if the 9" vs 8.8" would make a big enough difference to worry about in pinion length but I bet Randy's would be able to point you in the right direction. They have no doubt run into that question before.

The problems with a late model 8.8" with disc brakes:
- wrong bolt pattern. You can fix by re-drilling the rotors with the correct pattern and installing lugs in the new holes. Measure carefully.
- what are you going to do for an e-brake?
- you might have to relocate spring perches - do you have the tools and skills to do so?
- drum brakes require much higher PSI than discs. I don't know what else you would have to change. Prop valve maybe? Not sure about the master cylinder.
- you probably won't notice much of a difference at all in braking performance.

IMO, rear discs are a nice to have. If you're towing a lot or braking performance matters a lot for your application, then go for it.

 

On the same subject, my 97 with the 8.8 3L55 crapped the spider gears today. I ordered, by some miracle, new ones for tomorrow. However, I have never done a a rear end before, having always been of the belief that they require something to the left of witchcraft and possibly a blood sacrifice. My question is, can I do the job without taking the whole rear out of the truck? I just need to get up and running so I can make some money to save up for a new rear.