I agree, definitely an internal issue with the 3rd gear synchronizer assembly or the small teeth on the 3rd gear. Bill

I spoke to Paul Cangialosi yesterday and sent some pictures of the trans to him and he said the issue was the prior builder of the transmission used a locking third gear with a non locking slider. He also recommended hardened hubs, new sliders, and new shift forks. I’ll post some pictures when I revise receive the parts and start the tear down process.

Paul's an awesome guy,he's been a huge help over the years with parts for my M22s, and Top loaders,
and he was the only person in the country that was able to come up with a 6th gear set for my Richmond when I had all but lost hope.

I agree, he’s been extremely helpful in this entire process. Couldn’t ask for better or faster customer service. I called and sent some pictures to him, it was immediately diagnosed and he had all the parts in stock and shipped them the same day! I have received the parts and started the process. I must admit, I’ve never disassembled a transmission before so it was a little intimidating but with Paul’s help and his book on Muncie 4 speeds, it’s been a very straightforward process.

I was able to make some more progress on the Muncie this weekend. The main drive assembly is back in the case, new seals have been installed in the extension housing and it has been reinstalled. Only thing left now is installing the shifter shaft seals in the side cover and putting the new shift forks in and it will be ready for the shifter to go back on.

Before I pulled the trans, the clutch was starting to show it's age so it will be replaced with a fresh one from Hays. I'll have the pressure plate balanced with the flywheel after it's resurfaced. I had this done on the first clutch and it made a significant difference in the smoothness of the driveline.

Update:

The Muncie is now back together. I replaced all of the bushings and retainer springs with a kit from Paul, and the difference in how the parts fit together is night and day. There is no more slop in the rods/levers. I also realized since my trans has the stud type shifter shafts, I need the spacers Paul sells to take up the slop in the slots that locate them on the shafts, so I've got those on order.

I used the bread trick to get the pilot bearing out of the crankshaft, and then I cleaned it up so that it's ready for the oilite bushing to go in and reassembly. I've got the bushing in the freezer so hopefully when I install it, it will go in without damaging it. I found that the national bearings brand bushing part number PB-656-HD is non-magnetic as many in the parts store are and those can damage the input shaft due to the iron content.

Pressure plate and flywheel will be balanced this Thursday so hopefully I can get the car back together this upcoming weekend and test out my hard work! I think it will be a tremendous improvement from what I had before.

Never heard of using bread to push a bearing out. Must need half a loaf to get it compressed enough to create pressure. I always use chassis grease and an old input shaft for that. Probably messier to clean up than bread crumbs.

I think I used 3-4 pieces. It was much cleaner to deal with than grease for sure!

So, do you just beat the bread in with a rubber mallet? What is the procedure?

I tore the bread into small pieces and pushed as much in as I could by hand through the hole in the pilot bearing. Once I could get no more in there, I took a 10mm 3/8" drive socket, and a 6" extension, lined the socket up in the hole and hit the end of the extension with a hammer to compress the bread. I didn't have an old input shaft to use for this. I would then continue to add bread by hand after it was compressed and repeat the process until I got the bearing out. Took me about 15 minutes. I tried to use a pilot bearing removal tool, but after 5 tries and it not working, I went to the bread, haha.

https://youtu.be/Lbao3zkxV3c for reference