yoke snap rings

[Timothy B.]

My question is about snap rings that hold the yoke into the differential case. These snap rings have a rounded side and sharp/flat side. I looked in archives and found conflicting info about how they are installed.

Can someone explain the proper orientation when installing these rings. I had them rounded side inboard toward differential pinion gear pin but decided to turn them around.

One final question, are there thrust washers on differential pinion gears for non posi rear?

Thanks as always, Tim

[Chuck S.]

Re: yoke snap rings

My question is about snap rings that hold the yoke into the differential case. These snap rings have a rounded side and sharp/flat side. I looked in archives and found conflicting info about how they are installed.

Can someone explain the proper orientation when installing these rings. I had them rounded side inboard toward differential pinion gear pin but decided to turn them around...

Tim, I hope you didn't pull your diff to get those clips rignt.

I'm thinking the rounded/flat edges are only a by-product of the stamping operation, and it is not purposely designed that way, but maybe I'm totally in the dark. In other words, when the die stamp contacts the sheet steel, there is a momentary resistance (probably ten thousands of a second) by the steel until the die overcomes the hardness of the material and shearing begins. That results in a slight depression or rounding of the top material surface. I have never seen a flat washer that didn't have a flat side, and a rounded side...I always install the flat side down against the material, rounded side on the nut side (No doubt, some guys are saying "Huunnngh?" about now. )

My opinion on installation is that if they're not marked "green side up", then it don't matter. I would probably install the rings such that the sharp edge contacts the differential case, with the rounded edge to the inside or unloaded side. On the ID, the rounded edge will then contact the groove surface in the yoke, so pick your poison...you're going to get one sharp edge and one rounded edge in every installation when loaded. Does it make a difference which is which?...I highly doubt it.

But...hang on...maybe a more technically minded person will straighten me out.

[Joe L.]

Re: yoke snap rings

Tim, I hope you didn't pull your diff to get those clips rignt.

I'm thinking the rounded/flat edges are only a by-product of the stamping operation, and it is not purposely designed that way, but maybe I'm totally in the dark. In other words, when the die stamp contacts the sheet steel, there is a momentary resistance (probably ten thousands of a second) by the steel until the die overcomes the hardness of the material and shearing begins. That results in a slight depression or rounding of the top material surface. I have never seen a flat washer that didn't have a flat side, and a rounded side...I always install the flat side down against the material, rounded side on the nut side (No doubt, some guys are saying "Huunnngh?" about now. )

My opinion on installation is that if they're not marked "green side up", then it don't matter. I would probably install the rings such that the sharp edge contacts the differential case, with the rounded edge to the inside or unloaded side. On the ID, the rounded edge will then contact the groove surface in the yoke, so pick your poison...you're going to get one sharp edge and one rounded edge in every installation when loaded. Does it make a difference which is which?...I highly doubt it.

But...hang on...maybe a more technically minded person will straighten me out.

Chuck and Tim------

I agree with Chuck. I've always considered that the "rounded" versus "sharp" side of the snap rings was a result of the stamping operation that produced them and not an intentional, design feature. However, "intuitively", I've always installed them as Chuck describes, but I really don't think it matters.

By the way, in service literature, GM does not instruct any "directional" installation of the snap rings.

[Timothy B.]

Re: yoke snap rings

Thanks Chuck for your opinion, no, I did not pull the rear to check snap rings.

I installed these with the sharp edge toward center so there is less tendensey for them to pop off if the yoke is pulled outward.

[Gary R.]

Re: yoke snap rings

I've looked at many originals when rebuilding them but to be honest never really saw a difference. I agree with the others. I'm doing a virgin 65 open now in fact and the rings have little difference in them. If a ring pops off usually it's from other reasons, like not fulling seating them.
The diff I'm doing I'll be reusing the yokes as they had no wear at all on them. This build is on digital if you want to take a look.

[Chuck S.]

Re: yoke snap rings

...I installed these with the sharp edge toward center so there is less tendensey for them to pop off if the yoke is pulled outward...

That is probably not a bad plan either. Maybe it could be argued that the cast iron of the case is softer than the hardened yoke, and therefore, the yoke groove can better tolerate the "sharp" edge, and the softer iron will be better off with the radius.

For pull out, it won't make ANY difference so long as the "groove depth" in the yoke and the contact area in the case is many times greater than the radial clearance movement of the ring on the yoke plus the radius of the "rounded edge".

Trust me, there's no doubt that GM had some young engineer in training taking a hard look at that clearance number and then quadrupleing the required groove depth to maintain several times that in interference. He would also have looked at the width of the snap ring, side to side clearance in the groove, etc. to insure that the moment required to roll that ring out of the groove was impossible to achieve.

There was no way the General's engineers would leave Mr. Goodwrench a chance to get those rings in upside down...if it really mattered (JMHO).

[Timothy B.]

Re: yoke snap rings

Thanks Joe, Gary and Chuck, I appreciate the info. Gary, Where can I find digital (what is it), I would like to look at your overhaul..

My other question concerns differential pinion gear thrust washers on a open diff. Parts book pic does not show them but they are listed under that group # in the GM parts book..

[Gary R.]

Re: yoke snap rings

Here is it.

http://www.digitalcorvettes.com/forums/showthread.php?p=1612015#post1612015

[Chuck S.]

Re: yoke snap rings

Thanks Joe, Gary and Chuck, I appreciate the info. Gary, Where can I find digital (what is it), I would like to look at your overhaul..

My other question concerns differential pinion gear thrust washers on a open diff. Parts book pic does not show them but they are listed under that group # in the GM parts book..

Do you have a Helms component overhaul manual for your year car?. I looked for my 66 version around here, but it's temporarily lost.

The diff is covered in the overhaul manual...if it says to install thrust washers, then do what the manual says. I would figure it should have them since a thrust washer is usually a replaceable wear surface

[Joe L.]

Re: yoke snap rings

Do you have a Helms component overhaul manual for your year car?. I looked for my 66 version around here, but it's temporarily lost.

The diff is covered in the overhaul manual...if it says to install thrust washers, then do what the manual says. I would figure it should have them since a thrust washer is usually a replaceable wear surface

Chuck-------



...and often hardened to a much greater Rockwell hardness than the surface it protects.

[Timothy B.]

Re: yoke snap rings

Gary,

Thanks for the pictures of the 1965 rear overhaul. This open rear is dated May 1964 but I don't see any differential pinion spider gear thrust washers like in your pic. There are side gear shims that measure approx.030 and I don't see them in your pictures.

[Gary R.]

Re: yoke snap rings

There were both thrust washers and 030 side shims in there. I rebuilt it with all new parts. The washers will change the gear mesh,although the lash is set up by the side shims. This 65 was never worked on from what I saw so I believe it to be correct. The mesh is good,these are not tight like the posi spiders are. There was no wear on the yokes at all. If yours was opened up in the past then anything could have been done. Be sure they're not too loose or tight.

[Dick W.]

Re: yoke snap rings

I have always used the same procedures as you would on piston pin locks. The sharp side goes against the pressure, rounded side out. Pin locks will work themselves out of the grove if you do it backwards. Not a pretty sight See my next post, this is bass ackwards

[Timothy B.]

Re: yoke snap rings

Dick, so what is the pressure side, when pulling out on the yoke, is it the inside groove in the yoke or the side gear where the snap ring would hit.

Gary, are these pinion gear thrust washers still available from GM or where do you get them.. I thought the thrust washers will push the pinion gear inward decreasing backlash. The yokes on this rear check at approx .008-.010 end play so I don't think they are wore much.

[Dick W.]

Re: yoke snap rings

My post was bass ackwards. The rounded edge goes against the pin, the sharp edge goes away from it. The thrust of the pin will cause the sharp edge to bite into the piston.

The load on the stub would be when it pulls out. The rounded edge would go against toward the yoke, the sharp edge toward the differential.