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Three Speed with Overdrive Reference Photos


James_Douglas
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Hi All,

 

I have my spare three speed with overdrive all torn down and am starting to get in the replacement parts. I took some photos of all the parts. In the event that anyone would like some reference photos, I decided to post them.

 

The painted case is the one I cracked 15 years ago. It could be welded, but I found a NOS one to use. If anyone has a OD Planet assembly with stripped out gears I would love to get it and see if I can get the shield off nice and if one can get the pinions out of it. If a method can be found to do this then going to some gear makers may we worth the effort to be able to rebuild the pinion (planet) units.

 

James

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Posted (edited)

What a PITA!

 

So, one of the things that has made my transmission, not the overdrive, run so nice is that I held very close to the bottom end of all the specifications for end play on everything. Like the second gear at .003. (Second gear is supposed ot be .003 to .008)

 

Well, I pulled the NORS main shaft, the NORS clutch gear (Syncro) and the NOS second gear. I clean them all good and placed them on the clean shaft and took a measurement. What do I get? I get .012 to .014 inch. F&*#&#&#&K.

 

I used the largest snap ring that is made which is .097 inch. 

 

So, her we go again. I will have to take the second gear to the industrial hard chrome shop and have them plate the back side of the second gear to make up about .010 to get it to .003 to .004.   That costs more than the gear itself. I tried the old clutch gear and it comes out a little better about .008 to .010.

 

A classic case of stacking tolerances, but in this case in the wrong direction.

 

One could see if a larger snap ring can be found, it would have to be one larger than the factory ever showed in their parts books, and lathe the groove open to take it. The only problem with that is that it would push the clutch gear back and affect the position of the shift fork. I think plating the rear of the second gear is probably the best thing to do and it has worked for 15 years on the current trans.

 

Time for a drink!

 

James

 

Edited by James_Douglas
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Hey Sniper, Shims do not work well in transmissions. They tend to get ground up and then they fail and ball up and make a mess. That is why I plated the last one.

 

I have order another clutch gear. Perhaps I will get one that is a hair thicker and that will help. If not, then off to the industrial hard chrome shop it goes...

 

James

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I've had more Mt. Dew and more time to mull and see the true intent...I've hidden the relavant posts.  Just watch the phrasing and be clearer on intent and things are fine.

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25 minutes ago, Young Ed said:

Asking about a vendor or part from a company is different than trying to buy off another forum member

 

 

That's a very thin hair to be splitting.  It sounds like if James had simply said "Anyone know where I can get one" he'd have been ok?

 

Which is why I asked the moderator for clarification.  Heck, I can't find the rules, must be getting old, lol

 

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24 minutes ago, Sniper said:

 

That's a very thin hair to be splitting.  It sounds like if James had simply said "Anyone know where I can get one" he'd have been ok?

 

Which is why I asked the moderator for clarification.  Heck, I can't find the rules, must be getting old, lol

 

It makes sense though. If someone comes up with a vender or part source that could be useful in the future if it's stored and searchable. No one wants to store or find in searching old conversations where Fred and Earl are swapping parts. 

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Just wondering:

If you can ask for help with a problem and that’s okay and expected, then why is it unacceptable to mention you are looking for a worthless junk part as a set up piece?

In this thread the offering is for reference, to expand the knowledge base. I should think that is a noble purpose with no intent for personal gain.

I see posts mentioning venders all the time. Some of those venders use this forum’s members to work out how to make their products actually work! I personally find that unacceptable. Commercial gain with no responsibility to document how the product is supposed to be used? You will find post after post of people struggling to work out issues with these products and not one complaint about the lack of documentation from the vender.

If it is important to protect the members from the commercialization of the forum, then each and every post that mentions a product from a vender who does not include detailed documentation should include a disclaimer by the moderators of that fact and the fact that members have had problems making that product work.

Just sayin’

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1 hour ago, JBNeal said:

Fred and Earl sounds suspiciously like Ed and Merle... 👀

Funny OT story one of my highschool buddies called me and a third friend Fred and Earl. We were really Ed and John and we always assumed I was Fred but she never said for sure. 

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  • 3 weeks later...

One of the big problems I am running into is that even with NOS and NORS parts that getting the second gear to be well under .008 is not going to be easy, quick or inexpensive.

 

I have tried one NOS, one NORS and three used Second Gears. I have tried these with two used main shafts and one NORS main shaft.  None of them are under .008.

 

The NOS second gear that was in the transmission, not making any noise that I plated 15 years (60K miles) ago and is .004 clearance has a gear tooth that was cleanly severed at the root! I have no idea how or why that happened. The transmission also had a part of the reverse idle gear that had a tooth cracked off. It is possible that the reverse gear part got into the second gear and caused the problem.

 

I have thought about turning on a lathe the clutch gear stop back on the main shaft .005 to bring the second gear to about .003 to .004. I would have to use a thicker snap ring to push the clutch gear back. BUT, this would push the syncromesh to the rear the same amount and the relative angles of the syncromesh teeth are critical to proper and quiet operation. I worry that moving it back will cause and issue with the input pinion syncromesh teeth.

 

As to Snipers comment...yes shims are used in modern transmissions. But the design of them was built from the ground up to use them with plenty of thrust surface on both sides of the shims. The design of our MOPAR three speeds is not one of them. The "flutes" on the back of the second gear may well chew up any shim. Also, we are looking at something on the order of .004 to .005 shims, not .010 or .020 in thickness like may modern transmissions. I think using something so thin that does not have a wall height of at least 3/4 inch and corresponding thrust wall height is playing with fire. The flutes one the one end and the brass syncromesh gears on the other make it not possible to have a shim with any appreciable wall height.

 

The only thing I can think of that keeps all the syncromesh geometries as the factory intended is to either move the flutes forward about .005 which is not really something that can be done easy or make the rear side of the second gear thicker to make up the distance.

 

I may have to put a set together to get the car running and just know that second gear my make noise, or it will in the near future, as it is not within the 0.008 or less specification. The MOPAR service booklets make it clear that anything approaching .008 will start to make noise.

 

I then can take my time to get the other transmission built up when I get the second gear rear face chrome plated. In fact, I am going to buy a couple more second gears and have several done so I never have to deal with this particular issues again.

 

James

 

 

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I just spent the last couple of hours going through three used and one NORS main shaft and several sets of second gears and clutch gears all NOS or NORS.

 

I found that the NORS main shaft was worse as to end play than the two used main shafts. I also found a difference of about .002 in thickness of the NOS second gears.

 

By playing mix and match I was able to come up with a set that is at about .005 or .006 inch. Now this is with parts not perfectly clean, I cleaned off the cosmoline with a razor blade but not perfectly clean. So add about .001 for that.

 

At .007 it is within specification by .001, but the good book says that anything close to .008 should be replaced or it will get noisy in time. All that said I went back and measured the shaft, clutch gear and second gear with the bad tooth and it is about .012 after 60K miles. It was not making noise.

 

I am going to build this trans with this set up to get it back on the road. In the next couple of weeks I am going to take two more second gears down to have them industrial hard chromed to add enough so that I can use the NORS main shaft in the spare trans and have one extra second gear as well.

 

I am hoping the by chroming two or three I can get the unit cost down, but it is likely to be $100 to $200 per a gear.

 

James

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  • 3 weeks later...

Ok,

I am sitting on my hands as the proper pinion bearing is back ordered. Someone higher up at SKF was very nice and found two and released then to distribution so I could order them. Now the bad weather in Nashville is slowing down UPS so my 2 day air is not going to get here today.

 

While I wait on that and the grease, I took apart the bad planet assembly.

 

I used a dremell cutt off wheel and slit through the tin steel cover and slightly into the forging. I then was able to pry back enough to get it to come off. I do not think the slits will cause stress raisers and in any event when I put it back on I will mig weld three tacks and that should get it back on and prevent and cracks.

 

The thing you cannot see in the photo is the blind pin that hold the center race in is in two parts. When you drive or press the center out the pin shears off clean and easy. The part in the body is easy to pop out but the part in the center race shaft is blind. Too some work to come up with a way to get it out.

 

So now I need to look into making new center shafts as the one that failed as well as the other are showing since of the needle bearing going through the case hardening. Then I also would need to find a set of needle or other bearings and the thrust washers. The tough part will be finding out how much for a gear company to make new planet gears...

 

It is something that can be done and if it is one would have a new planet assembly. But the time and money will not be trivial.

 

James

 

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What is interesting is that on the gear where the needle bearing failed, the washers that act as the thrust bearing and hold them in were no place to be found. They were ground up completely, along with 2/3rds of the needles, which is very odd. There is a fair amount of material in the ring gear bottom grooves and as the planet assembly rotated it pounded that material in fairly good. No doubt that is what was making the noise. It appears that the gear itself with all the needles gone backed away from everything and just went for the ride. It does not look like ones I have see online where the gears are stripped out.

 

Interesting....

 

James

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