ok i know this has been kicked around in the past but i was not here then so maybe we can tap it around a little now. i would like to be educated a little on why i need the snap rings on the side yokes. here's my story.it's a 71 coupe and i wanted to put a 3:70 in to replace the 3:23's. i wanted a spare to set up the new gears so i answered an add for a 78 part out and purchased a 3:23 posi for a fair price so i had my spare. when i got it home and lifted it out of my trunk the side yokes came all the way out and i thought to myself oh sh--,this is going to be a mess inside. i was thinking i should have looked it over better. as i looked at the side yoke ends they looked like they were in very good condition so i miked them and they were about .185 from snap ring grove to the end of shaft which is about perfect and they showed no signs of wear. i then took the backing plate off and the inside looked to be in very good condition including the posi unit. the outside punkin had about a million miles of grease on it so it was probably not brand new and it was a part out to begin with. now here we go with the snap rings because there were not any installed. i have a friend who was a career vette mechanic so i talked to him about this and this is what was said. he said how many times have you heard of the snap rings coming out and being lodged in the bearings,bottom of the case and worse yet smashed in the ring and pinion? he never put them in when he was working on them. my carrier shaft was in perfect condition so it was not wearing in that area and the outer part of the case where the snap ring would hit had no wear. it was said that the yoke would come out without the snap ring but how would that happen with the half shaft bolted to the trailing arm unless all four bolts sheared off. he said the snap rings have nothing to do with yoke in compression because the yoke hits the cross shaft and unless something is way off nothing to do with the yoke if pulled out against the case. as i read the forums here and elsewhere the number one reason i have been told you need the snap rings is because g.m. put them there and thats good enough. i'm getting ready to install my punkin with new u.s. gears and would like to be educated on why i would need these rings.i'm not too old to learn(will be 70 saturday) and would tip my hat and thank you for the reason for the snap ring installed and why. thank you everybody in advance and i will probably have some questions about this later. ps sorry for the long thread.

 

Some guys in the C2 forum don't use them and have not had any problems. Has advantages too for not using them. So, read this. It should answer your question depending upon what you want to believe.

https://www.corvetteforum.com/forums...-movement.html

 

very interesting, thank you very much.i'm sitting here right now looking at the side yoke trying to figure out how the snap ring would do anything other than hold the yoke in during installation.read many forums about the rings being smashed up in the diff. don't want that to happen to me.

 

Charles, one very good reason to have the snap rings in the Corvette IRS is that the half-shaft is acting as an upper control arm to control rear wheel camber. Without the snap rings the stub axle/half-shaft will move in and out freely as the car corners and constantly vary the rear wheel camber.

You might find it useful to read through this thread for some pretty good info on the usefulness of the snap rings and even how to address the potential of them failing. I would start at post #17
https://www.corvetteforum.com/forums...ch-system.html

I have never personally heard of a snap-ring tearing up a ring & pinion on one of these rears. I'm not saying it hasn't, I'm just saying I haven't heard of or experienced it.

I have however seen a number of these rears that sheared the heads off of the bolts that hold the ring gear to the posi. If they work loose, they will start to back out until they strike the reinforcing web in the rear cover and make a "clicking" noise until the web snaps the head of the bolt off. Another will come loose and start clicking until that head gets snapped off, and so on until the ring gear spins freely or one of the bolt heads finally causes enough damage to stop things. I now always check any used rear covers for evidence of damage to the web for that reason. I have found more than a few that show the damage. I also always check the tightness of the ring gear bolts whenever I remove the rear cover, particularly so if there are no lock washers on the bolts.

Good luck... GUSTO

 

thanks for the info gusto. Lars always has good stuff.i was reading on one of the forums,don't know if it was this one or another about a friend of a guy that had a snap ring come off at about 60 mph and locked up the rear end. i'll try to find it.i can see the stub shaft wearing like Lars said but the snap ring seems to be doing nothing but going along for the ride when it wears on the inside like that. things are pretty bad by the time it gets to the snap ring grooves.the way those guys harden and machine the stubs for a pressed in insert is way out of my range and budget.don't have the machinery to do that stuff. it would be good if a retired gm employee that worked in the diff. assembly plant would chime in. thats a long shot but you never know. it just seems that when the trailing arm goes through it's arc the snap ring would hit the outside case on one swing and hit the diff pin on the other swing. hitting the pin would wear down the stub end like Lars said. still thinking about it. things like this bug me a little.

 

I used to consider that the weight of the car would always exert inwards pressure on the pinions, but seeing this video takes any personal opinion out of the equation...



I installed circlips when I rebuilt my diff 8 years ago. Thank heavens I did.

But conversely, unless you have installed upper rear arms, why would you not install them??

If correctly installed how would they fall out under normal conditions?
How much are they, $1?

I can't see any reason not to install them

 

wow blue juice that's a lot of movement. just for the record i have 2 new snap rings on the work bench waiting for all the opinions to show up. that stub shaft seemed to come outward a lot which would put a lot of pressure on that little snap ring. no wonder some of the guys found the snap ring in the bottom of the case. not anything like the c-clip in my 12 bolt. when i google snap rings or no snap rings for the c3 i'm set for the next 2 hours reading about them. most failures were where the stub axle rubbed against the carrier pin and the ring fell off the end. i hope some of the guys that had this problem will chime in.like i said in previous post i have had some very good career corvette mechanics say to leave them out. also had a guy say that the snap ring groove was not deep enough on the yoke which allowed it to slip off.he cut his groove deeper to eliminate the problem. thanks for the reply.

 

Douglas, thanks, that was the very video I was thinking of as I wrote my above post. That video illustrates pretty clearly why the clips are important. The effect is exactly the same as having strut rods with worn out bushings in them, extremely erratic camber.

Having said that, if you always drive your Corvette in very tame manner, you may never notice that the clips are missing. I have read more than a few posts over the years where folks were surprised to find a clip or clips missing when disassembling their rear or changing out half-shaft U-joints.

Good luck... GUSTO

 

I should make it clear, that's not my car and not my video.
And there are far, far more experienced differential guys on here than me.

But I did rebuild my own 1976 diff with new ring gear (308 out, 373 in) and tuned the posi, using solid clutch plates and removing the springs in the process.
I did all this with parts sent to me by Gary Ramadei.

I think, like anything you buy, you get what you pay for.
I wanted top of the range parts, and Gary always advocates this too, so I had Tom's hardware throughout.

My understanding is that the GM spindles in the late 70's early 80's were notorious for being soft and wearing or mushrooming.
If you use good replacements with the correct dimension circlip groove, then you wont have any issue.

As with all jobs; when you install the clips, ensure they are correct and put quality into your workmanship.

The amount of force pulling the pinion in the video won't be that great, but the fact that a pulling force can occur is reason enough to ensure the clips are installed

 

Only a fool would not install the clips on the yoke.. GM was not stupid, they put them on to prevent sideward movement .. But if you think you are smarter than the engineer who designed it, by all means leave them out...

 

Gary set me straight on the ring and pinion. used u.s. gear from Toms.he also helped with the gear pattern on final setup, great guy.

 

thanks for the reply. i don't think i'm smarter than the engineers, just getting opinions on a rebuild,also not in the fool calling business.stubs and pinion bolt look good so i'll reassemble with good snaps and go from there.

 

I have no opinion regarding leaving the clips out. FWIW, I installed mine. What I will comment on is your point on GM engineers. While you are correct that they weren't stupid, their motivation wasn't always in the best interest of the car owner. They were motivated by a number of factors including cost and convenience of assembly. By the sound of the car in the video, I would hazard a guess that the owner decided that GM engineers fell far short in the power department.

 

You only need to jack your car up and see the side yoke move to understand why the clip is there... yeah, they may have cut a corner to lower cost but this could be a serious safety issue at high speed cornering..

 

wasn t calling you a fool...you haven t left yours out yet... perhaps read it again...

 

Depending on how your snap rings are made...if they are stamped out and have a rounded edge...and the other edge is quite flat and sharp and defined......stop and think about how you actually clip them on. As I have been told...and how I do it...they really need to only go on one way.and that is the sharp defined flat edge of the clip faces towards the END of the side yoke where your U-joints go...because when the yoke is trying to come out....having that sharp defined precise surface fitting into the groove of the side yoke has a better chance of staying put.

Hopefully that makes sense...and this procedure is what I employ on ALL clips that I install. I look at the clip and if there is any movement..I make sure the clip is positioned so the clip is locking into the groove and less likely that it can slide or pop off due to a rounded edge of the clip.

DUB

 

i know fish,we're good. the plan was to make the swap about november. i'll revisit this then. got some good seat time today. went over some small bumps in the road today at speed limit and the car wanted to go where it wanted to go and not where i was steering. does not seem safe above 60 mph. scared the hell out of me for a few seconds. have some koni's on the shelf for the rear and i'll have to get some good dampers for the front and have the front aligned to start with. always something with these early c-3's but i love it.

 

thanks DUB. i have read the same as you said.when i make the change next month i'll check my originals that are in there now.had it up today and it passed the eyeball test so far.both stubs looked good in there.i'm just having a hard time thinking that the little snap ring is what keeps the yoke in. when i look at it i see a u-joint on the other end connected to a half shaft and the other end with a u-joint bolted to the trailing arm.seems like the only way the yoke could come out is for the half shaft to blow up which is probably rare. don't see how the snap could do any good with pressure going in towards the center pin. i keep seeing pictures of the stubs mushroomed out from wear on the end and cannot understand how the snap ring clearance could have stopped that. have you ever seen any wear on the case side where the ring would rub? just wondering. anyway thank you for the reply.