Synchro Stop Ring

[52b3b Joe]

It's been a while since I made any posts, but has anyone had a pin style synchro stop ring fail in their truck? I took my truck on a 2.5 hr trip to pick up a new toy (hit and miss engine) and on the way back all of a sudden I had no synchronized shifts going into second. I drove it again a couple times since with no change, so last night I thought I'd drain the oil and see if any metal was in the case. Sure enough, I pull a broken off pin to a synchro stop ring. I was curious if this was common. I'm happy the pin didn't run through any gears and chew up any thing. I guess I got luck. from what I can tell, they used that same stop ring into the mid 70s by crossing the part number over. I have a new outer and 2 new inner rings headed my way via eBay. Hopefully I can tear it apart and fix it quick when the parts show up. 

[JBNeal]

I'm glad that ya avoided a crunchy disaster and got parts coming for a fun repair...

but that stainless grille offsets all the blah with snazzy looks?

[52b3b Joe]

7 minutes ago, JBNeal said:

I'm glad that ya avoided a crunchy disaster and got parts coming for a fun repair...

but that stainless grille offsets all the blah with snazzy looks?

 

You're not kidding, I was beyond lucky on this one. I'm starting to lean toward installing my spare transmission while I fix this one. The spare is a crunchy shifting and noisy SOB. It needs bearings and synchros at minimum, but it should survive a month or so to keep the truck driving. 

 

There is nothing wrong with the boring steel grills ? lol...but nothing beats the stainless. My COE just lacks some bling every time I see it! 

[JBNeal]

Why not try some stainless steel in a can?  ?

 

https://steel-it.com/pages/automotive

[wallytoo]

3 hours ago, 52b3b Joe said:

 

There is nothing wrong with the boring steel grills ? lol...but nothing beats the stainless. My COE just lacks some bling every time I see it! 

 

pics of the COE!  i'm sure i missed them in the past...

[Dodgeb4ya]

I have seen two or three broken pin type syncro's.

They do shift smoother than the strut type.....when the pin or pins are not broken.

[ggdad1951]

Trash the whole thing and send me your grill bars! 

 

Glad to hear things went as well as they could.  What trans you have in him?  I only have syncro in 3rd and 4th.

 

 

[52b3b Joe]

13 hours ago, wallytoo said:

 

pics of the COE!  i'm sure i missed them in the past...

 

Here's a couple. It's a project. Most likely going to sit a while longer before I get to it. It was in a barn that was falling down when I heard about it. It was going to be destroyed if I didn't get it out of there, so at least it was saved! 

[52b3b Joe]

4 hours ago, ggdad1951 said:

Trash the whole thing and send me your grill bars! 

 

Glad to hear things went as well as they could.  What trans you have in him?  I only have syncro in 3rd and 4th.

 

 

 

I went through hell and back with those grill bars! I'll go to the grave with them besides me lol.

 

Just a 3 on the tree standard 1/2 ton trans. 2 and 3 are synchro. 

[52b3b Joe]

11 hours ago, Dodgeb4ya said:

I have seen two or three broken pin type syncro's.

They do shift smoother than the strut type.....when the pin or pins are not broken.

 

It does shift nice when its working. I guess it's a somewhat rare failure but I'm glad someone else has seen it. 

[wallytoo]

20 minutes ago, 52b3b Joe said:

 

Here's a couple. It's a project. Most likely going to sit a while longer before I get to it. It was in a barn that was falling down when I heard about it. It was going to be destroyed if I didn't get it out of there, so at least it was saved! 

 

 

looks pretty good.  probably could run it with attention to mechanical issues and repairs and leave the sheetmetal alone.

[ggdad1951]

1 hour ago, 52b3b Joe said:

 

I went through hell and back with those grill bars! I'll go to the grave with them besides me lol.

 

Just a 3 on the tree standard 1/2 ton trans. 2 and 3 are synchro. 

 

aw...c'mon!

 

Ah 3 on the three explains it....not as familiar with those as the 4 on the floor.

[52b3b Joe]

1 hour ago, wallytoo said:

 

looks pretty good.  probably could run it with attention to mechanical issues and repairs and leave the sheetmetal alone.

 

That's kind of what I'm leaning towards. The engine is loose and I don't think it'll take much to get it running. With a growing family, work, and keeping up on everything we own, there isn't much down time! 

[wallytoo]

1 hour ago, 52b3b Joe said:

 

That's kind of what I'm leaning towards. The engine is loose and I don't think it'll take much to get it running. With a growing family, work, and keeping up on everything we own, there isn't much down time! 

 

been there, done that.  still enjoying it, too.

[jpellican]

I would interested knowing the ebay site you got the schyronizer from I have been looking for the inner brass rings for 3 speed for some time now with no luck. The schyronizer assembly should be a awt234-21/2a. You can pm me.

[52b3b Joe]

As a follow up, I thought I'd share what I found. I finally had some time yesterday, so I pulled the trans and tore it apart. It proved to be a little frustrating that I had hoped and I ended up not following the service manual. The front bearing retaining nut is staked on and short of cutting it off, it wasn't going to move. I took it apart by dropping the countershaft then splitting the bearings on the main shaft to pull everything out of the case. I made a pipe to replace the countershaft to drop it in the case, but I messed up and the rollers dropped out of the bearing. It was very frustrating to say the least. it didn't go very well.

 

I did verify that I broke a pin on one of the outer stop rings. I crossed the stop ring to a PN 2464839 which was used up until 1976 I believe. It does appear to be correct and it fits. All of the brass parts to the synchro's look like new, so the new outer ring is the only needed part. I also pulled my spare trans apart some to investigate because it shifted identical to my "good" one after the pin broke. Once I pulled the top cover it was easy to see that my spare transmission has the same issue, a broken outer stop ring. Everything looks very nice with very little wear in the spare one too. I'd have to say its the weak link of the transmission. I use my truck as a truck, and I wonder if the added loads of trailers/weight in the bed is the issue. Either way, I don't plan on changing how I use the truck. 

 

I have a busy month coming up, so I'm not sure when I'll reassemble it and reinstall the transmission, but I'll report back when I do. I'm hoping within a couple weeks before I forget how to assemble it!

 

[52b3b Joe]

To bring this to a rest, I finally got the transmission put back together and installed Friday night. I took it for a drive Saturday morning, and all is good. I only replaced the bad stop ring and both bearings on the main shaft. The transmission shifts smooth again, and it is quieter with the new bearings when the truck is sitting at idle. It always had a slight noise at idle from the transmission, but now all you can hear is the engine. It was very straight forward and easy to repair, I just couldn't find the time! Since I bought a spare stop ring, I think I'll repair my spare transmission this winter. It has the same problem and is already halfway disassembled. 

[John-T-53]

On 11/22/2021 at 1:36 PM, 52b3b Joe said:

To bring this to a rest, I finally got the transmission put back together and installed Friday night. I took it for a drive Saturday morning, and all is good. I only replaced the bad stop ring and both bearings on the main shaft. The transmission shifts smooth again, and it is quieter with the new bearings when the truck is sitting at idle. It always had a slight noise at idle from the transmission, but now all you can hear is the engine. It was very straight forward and easy to repair, I just couldn't find the time! Since I bought a spare stop ring, I think I'll repair my spare transmission this winter. It has the same problem and is already halfway disassembled. 

Hey Joe, is this still the same transmission that went across the country in a Fedex truck about 9 years ago?

[52b3b Joe]

19 hours ago, John-T-53 said:

Hey Joe, is this still the same transmission that went across the country in a Fedex truck about 9 years ago?

 

It sure is! It's been in use ever since it showed up. I've got a little over 5,000 miles on it now since I got the truck on the road. Not too many miles, but it's been hard to find time/opportunity to drive it since my son was born. Maybe I'll figure out seat belts and a way to retain the bottom seat cushion this winter to safely put a car seat in so I can take him with me.

[John-T-53]

2 hours ago, 52b3b Joe said:

 

It sure is! It's been in use ever since it showed up. I've got a little over 5,000 miles on it now since I got the truck on the road. Not too many miles, but it's been hard to find time/opportunity to drive it since my son was born. Maybe I'll figure out seat belts and a way to retain the bottom seat cushion this winter to safely put a car seat in so I can take him with me.

 

Good to hear that it's worked out for you, except for this new little situation with the synchro. Keep on truckin'!