Hey guys, I'm working on rebuilding my diff and it's becoming more apparent every day that I'll pretty much have to buy all new guts for it. It's been worked on at least once previously and I can tell that it's slung at least one ring gear bolt in it's past and who knows what else. When I got into it I found parts of at least two snap rings and what appeared to be a piece of spring floating around in it. Of course this is my first attempt at rebuilding a diff...

On topic however, I've removed the case from the housing and removed the ring gear. Now I need to remove the center pin and for the life of me I can't do it. One problem that this diff suffered from (in addition to the extra parts previously mentioned) is that the bolt that holds the pin in place was sheared. Between a 12 ton press and sledgehammer I was able to get the pin out far enough to remove the piece trapped inside it, but ultimately the pin still isn't coming out. I also removed the clutch springs, so compressing them isn't a problem. One hole for the pin was already misshapen and burred so I know I need a new posi case, and all in all I believe it's safe to assume I'll need a new pin (especially at the rate things are going...). I see no evidence of snap ring grooves (much less snap rings) on the pin so I'm really at a loss as to how to get it out.

Even if I have to get all new everything for it, I want to at least learn what I can from disassembly. Any suggestions?

 

Wow, so the bolt ( i think a 7/16 head) that holds the pin in place had its head sheared off and you were able to use a press to move the pin?

Once you remove that bolt the pin slides out pretty easy. I think you gotta get that bolt out somehow.

 

The bolt that holds the pin in place was already sheared to the width of the pin, not the head of the bolt unless by "head" you mean most of the bolt shaft as well. It's as if whoever worked on it previously used a much larger press than I have tried to remove it without taking the bolt out first. The pin itself rotates rather freely (even if pressed to one side or the other) but simply won't come out.

 

I guess I won't learn much trying to tear it apart then... How about suggestions of where to buy parts and what brand(s) to buy to rebuild the innards from scratch as apparently I have a rather expensive paper weight on my hands?

 

Search for Stinger12 diff. rebuild. Or contact, member Tracdogg2. There is alot of info here on diff. rebuilds, however your problem may need TD2's expertice. mike...

 

Yeah I've been reading up a lot on diff work here, there's a ton of good info. I put off actually posting until I was certain the question hadn't already been asked. I haven't yet heard of someone having a pin stuck like this. I guess I could try to drill one of the holes out if that would help, but again I don't think there's anything left to save and any further disassembly would be purely academic.

Besides what I've already mentioned, I was fully prepared to replace all the bearings and clutch plates. It's been highly suggested not to reuse gears (plus the spider gears are ever so slightly worn on the edges). I'm running out of things that I might be able to reuse...

 

This seems reasonable, though I lose the learning aspect by having it pre-built: http://www.jegs.com/i/Eaton/362/1967...oductId=750876
Can someone please verify that this is the proper unit or possibly suggest another vendor?

Unfortunately, they don't have a ring and pinion install kit appropriate for it, but I imagine the ring and pinion themselves (sans kit) should work sufficiently well. Eckler's is a bit more expensive but at least they have the right stuff so I could get the bearings/seals/gaskets/etc from there. Any suggestions?

 

I'm more concerned about the damage to the housing from the ring gear bolt backing out. This is a common problem on the later 70's diffs. Most likely the posi carrier is toast just from the ring gear bolt. If you can see wear on the edges of the spider gears then forget about re-using them.
Since you are having to replace everything do you want to go back stock or do some upgrades? What are your future plans for the car?
To do this job yourself you're going to need some special tools. Pinion set-up bearings, dial caliper and/or mics, torque wrench, and a strong impact and 1 1/8 socket.
Forget about places like Jegs etc for parts. They don't have what you need.
Mike

 

Here is what I did. I wanted to change my ratio from 3.08 to 3.55. Found a guy on craigslist who had a couple of rear ends for sale for $250. The one I bought needed seals on the axles. I popped the cover and saw the shafts were worn pretty bad. I took the axle shafts out of my 3.08 diff, cleaned it real good,put new fluid and gasket, ring clips and seals and put it in the car.

It worked great. I did not tear it completely down and pull it all apart. Then, I sold the 3.08 to a guy who wanted to do a gear change himself for... $250

It was a fair deal.

 

Hey tracdogg2, I'm pretty sure the case is fried. I'd love to build one up from scratch, but if I can get one prebuilt for a reasonable price I suppose that will have to suffice. The housing appears fine except for a little wear from losing the bolt, but it's not excessive. It's not unlike stinger12's when he wrote his paper. I'd like to keep the vehicle mostly stock, but I'm considering changing the ratio. Where would you suggest I go for parts? Jegs is the only place I've seen with pre-built cases and I haven't seen anywhere that sells just the case and/or spider gears etc. (yet).

johnt365, sounds like a good deal, I just wish it would be that easy in this case.

Again though, I'm up to the challenge of building and tuning one. Any tools I would need I will almost certainly use again in the future (I've got a '74 Porsche 914 that needs some serious lovin' and who knows what else I pick up along the way...) so I don't have any problems with buying them. Right now it's a matter of knowing where to get the parts I suppose.

 

If you are sure you're up to it I can walk you thru the whole build and supply the parts you need. There is not a single company that can supply all the good parts. Expect to buy a couple extra bearings. Most likely you'll damage the rear pinion bearing before you're done.
Tools you need:
dial caliper, a good one
dial indicator and mag base
press or the use of one
torque wrenches ft lb and in lb. The in/lb must be a dial, not click type.
1 1/18 socket
long punch
very strong 1/2 impact
a new sharpening stone
split type bearing puller
race drivers
set-up bearings
I'm sure I'm leaving something out but this is a start.
You need to consider your future plans for the vette, HP upgrades require diff upgrades.
I'll send you a pm for more details
Mike

 

easiest thing and probably cheaper in long run let mike do it for you then you'll know it will be right on

 

If you insist on a DIY learning experience, check out Pat Ikerd. He is a sponsor of this forum as can be seen on the left sidebar. A better option than Jeg's.

http://www.ikerds.com/catalog/group16/group16.html

 

Mike just finished rebuilding my '79 rear diff. I was going to tackle the rebuild myself until reading the forums here! All I can say is that Mike is an honest gentleman and a professional. He is THE EXPERT. He found issues that I doubt anyone else would have found. It is worth sending the diff to him and letting him work his magic. Good luck!

 

the nicest thing about mike is he will do all he can for the DIY

 

Yeah, I'm really appreciating the help he's giving me. I could send it to him to do, but again there's the DIY learning thing... I'll probably have to send my housing to him for some work, but so far I've gotten a ton of info from him and I'm eagerly looking forward to getting more. I also plan on rebuilding my TAs, so I'll be learning a lot about that from him too! My tool collection is growing by leaps and bounds at the same time.

 

I have to admit I felt pretty stupid when I realized what was going on with the stub axels (side yokes). I'm a new vette owner and most certainly new at diff work, so I figured this was some sort of retainer they used and most of the pictures I've seen were fuzzy enough that it seemed even some with snap rings actually used this style of retainer (doh!). That being said, I feel like an idiot and comparably I am. However, once I actually looked at the pic I took up close I noticed there was much more irregularity involved than I could see with my eyes (car work + glasses = blind). And to prove it (and hopefully add just a little justification to my idiocy) here's what I think is probably the best case of mushroomed yokes out there. (Note: I thought the one on the left was a bad retainer and the one on the right was good. At least now I know why there were snap ring bits floating around in my oil when I disassembled it...)

 

By "ones with snap rings" I mean pictures of replacements that had snap rings looked as if they had "these" types of retainers. I had come to the conclusion that it was some sort of cap that you press on once it's installed and isn't meant to come off again... not being exposed to this before, I was rather confused...