Trans Snap Rings

[James_Douglas]

FYI -

It is becoming apparent that one of the harder issues to rebuilding a MOPAR three speed the way the factory manuals recommend is securing the proper thickness snap rings.

My rebuilt trans has 2nd gear snap ring clearance of 9 thousands when checked in a jig with a dial indicator on the bench. The book states 3 to 8 with a strong preference to 3.

The clutch gear (inside of the synchronizer) is supposed to have zero. It had about 4 on my rebuilt transmission.

These two are the critical ones or second gear and the synchronizer can walk on the main shaft.

The big issue is that the correct snap rings in the sizes to make up for the wear on the main shaft do not exist. Production rings run from .078 inch to .093 inch to .109 inch.

It appears that the second with wear on the main shaft face runs from about .083 to .085. What I need is a set of rings from .080 to .094 inch on .001 increments for the second gear.

The synchronizer clutch ring groove is larger and until the second gear is fitted and installed you cannot measure that for the ring needed. However, I am going to estimate it tomorrow and come up with a range.

I am then going to call several snap ring makers and get a quote on making me up three sets of rings in the 0.001 increments.

If anyone wants in on a set or two, then let me know by posting a note on this thread.

Best, James

[Don Coatney]

James;

Would it be possible (read cheaper) to buy a thicker ring and have a machine shop with a surface grinder grind it down to size?

[James_Douglas]

Don,

I am hoping that the companies that make them have surface grinders and do it every day. For something so small a magnectic grinder is what is needed and the last piston shop that had one, for rings, in Northern California went out of business decades ago...

James

[James_Douglas]

Turns out that our 3-speeds are using snap rings that are not of any modern "standard size".

I cannot grind down to the proper thickness transmission snap rings as nobody has any in the ID-OD combination needed.

I found one spring maker that may make me a run as small as 100. But those 100 snap rings are going to cost me around $400.

The MOPAR service manuals are quite specific about having second gear between 3 and 8 thousands and the syncro at zero endplay. If these are not within specification than the transmission will run noisy and will cause abnormal wear.

I may spring to have a run maid and then try to recoup my costs over time. But I hat to have to sell snap rings at $5 each. If I do it, I may only sell sets of 10 for $50 and spread the pain around.

Now these comments apply to the three smaller snap rings. The small snap ring for the syncro cannot be checked until the second gear is set and in place with its final snap ring as the syncro abuts up against the second gear. These smaller snap rings are also not including the snap rings which hold the front, middle, and rear bearings in place. I still have to deal with those and the MOPAR service manual actually shows several thicknesses to get everything correct.

The three "small snap rings" are in their standard from:

ID=1.222

OD=1.475

Thickness is 0.088.

With this ring in place and a NEW second gear I am showing 7 to 9 thousands on the dial indicator using a magnetic stand mounted directly to the shaft for accuracy. The old was showing around 12 with the dial indicator. As an aside the dial indicator is showing about 4 thousands more than using a feeler gauge.

So I need a snap ring that is about 0.094.

Best, James

[Don Coatney]

James;

Is this snap ring issue what caused your original complications? I think not. Sometimes in life you have to go slightly sub standard and live with it. I think this may be one of those times. There are thousands of overdrive transmissions in service today that shift fine. You are looking for perfection in a less than perfect world. No matter what you do your Desoto will never be a new car.

[James_Douglas]

Don,

These rings are for the main trans. The spare trans is making a howling in 2nd and no doubt it is because of too much endplay. The manual goes into a lot of detail about this snap rings and end play.

In particular they talk about the damage that can be done to the OD if there is any movement in the rear or intermediate bearings. Given that the hard parts for the OD, like the main OD gear set, is just not available at any price, I will stick it out a little longer and try to find or make the correct snap rings.

I know that sometimes you just have to use what you have, but I am not at the point yet of tossing in the towel yet.

If I am still stuck in a week, I will have to toss in the towel or spend a hunk and make some parts up.

I did go the extra mile on the engine and other than the rear main seal leaking a little too much the engine really runs great and pulls that moose up those hills around here. I really want to have a trans to match the QA of the engine.

Best, James

[Mark Haymond]

James, I too am in the process of rebuilding an R10 overdrive transmission. I am willing to buy sets with you to help defray the cost.

[James_Douglas]

You know, I have one other thought...

At least on the 2nd gear, which also affects the syncro clutch, how about having the thrust face of the gear that rides on the snap ring hard chromed up by 6 thousands....may be cheeper than custom snap rings.

...James

[Mark Haymond]

Just a thought, why not chrome plate snap rings for different thicknesses?

[James_Douglas]

The groove....

[Don Coatney]

Just a thought, why not chrome plate snap rings for different thicknesses?

I would think the chrome plating would flake off as soon as the snap ring was expanded to install it. Chrome plating is not flexible, a snap ring is flexable.

[Plymouthy Adams]

actually...any plating done to an item considered to be a wear plate..this item should be nickel plated..it is tough stuff and wears like a pigs nose..I had a pretty good tangle with the local purchasers substituting cadium plate for items that are to be nickel plated due to this same reason..I had to call the factory for the engineering drawing and submit so as not to get a cheaper unsuitable part..they went on the fact the dimensions were the same and this one was cheaper...

[woodie49]

James,

I have just secured an R10 OD tranny. I have no idea what I will find when I open the case, but I assume at least a lot of wear. I, too, would be willing to help defray the cost.

Also, I will probably need a lot of help when I do the rebuild. You should make a video of the rebuild process to sell along with the extra sets of rings. Might be able to recoup the ring cost after all.

Jim