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Posted

I finally got around to trying to replace the third speed stop ring in my O/D transmission because it was worn and prevented the transmission from shifting into third. However, I can not separate the input shaft from the main shaft. I ended up removing both of them as one piece but they will not come a part. Does anyone know what would be holding them together? I have a parts transmission that I can use to replace the input shaft and the main shaft but the O/D main shaft has the "fast second" gear on it that I installed and I need to get the shafts a part to remove that gear.

Jim Yergin

Posted

Jim,

Are you talking about the input shaft standing up on the right and where it connects to the brass stop ring sitting on top of the syncro clutch just to the left of the input shaft in the photo ?

James

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Posted

Mine is longer due to the fluid coupling. Take a lead or copper hammer (or a rubber mallet) and whack it a couple of times.

The end of the input shaft is wedge shaped. The brass has grooves in it that can dig into the shaft over time. A few good whacks should get it apart.

James

Posted

James,

Unfortunately my problem turned out to be more than just the brass rings digging into the shaft. I "whacked" away on it but it would not release. I finally ended up using a cut-off wheel and cut the input shaft around the shaft to get it a part. Turns out that the the bearings failed in the input shaft collar where the transmission gear shaft fits. I assume that the oil hole in the input shaft collar got clogged. Some of the roller bearings actually ended up welded to the shaft and prevented it from pulling out of the input shaft. It appears that the roughness on the end of the shaft is additional metal from the roller bearings rather than gouges in the shaft. I plan on taking it to machine shop to see if it can be cleaned up. Unfortunately, this shaft is unique to the O/D so, unlike with the input shaft, I can not use the one out of my back-up non-O/D transmission. I am surprised that there was no horrible noise coming from the destroyed bearings before I removed the transmission.

Jim Yergin

Mainshaft004.jpg

Mainshaft003.jpg

Posted

Jim,

Before you spend a lot of money on the main shaft, slip the 2nd gear and the syncro clutch back on and check the 2nd gear end play. The flutes that the 2nd gear rides against on my shaft had worn and I could not get the proper end-play. I had my NOS 2nd gear hard-chromed to make up the difference because I could not find a NOS main shaft.

If it is ok with the 2nd gear end-play specification, the end of the shaft can be turned down and a hardened sleeve made. They freeze the end of the shaft in water-ice-alcohol mixture and heat the sleeve in a small furnace and then slip it on. Once done, it will not move.

It is interesting how the inner bearings in essence created a "locking key-way" in the main shaft. By the look, I think the shaft pitted then the bearings got destroyed by the pitted shaft and then the parts wedged into the pitted shaft.

Best, James

  • 2 weeks later...
Posted

It turned out, after removing the remains of the roller bearings, that the original surface on the transmission shaft was damaged. I asked my machine shop about sleeving it as suggested by James Douglas. I was told that it was too small of a diameter to do that. They suggested that it be hot spray welded, creating a hard surface, and then ground to original specs. I had them do it and here is what it looks like now. I am now waiting on some replacement snap rings before I reassemble the transmission. With the arrival of Spring and the return of decent weather, I am anxious to get the car back on the road.

Jim Yergin

Transmissionshaftrepair002.jpg

Posted

Jim,

One thing...

Put on the 2nd gear and the syncro hub with a snap ring. The hub should have ZERO movement. The 2nd gear should have between 0.003 and 0.008 with a heavy emphasis on closer to 0.003".

Even with a NOS 2nd gear and a NOS syncro hub the fluted ends of the main shaft splines had warn. I hard chromed my NOS 2nd gear to make up the slop. If you have a shop that can do a good spry weld then...

Check your end play on 2nd and if it is not 0.003 to 0.004 have them spry the ends of the flutes, mill them square, and turn them down as needed.

Do it now before you do anything else.

Best, James

  • 2 weeks later...
Posted

Got my transmission re-assembled but then discovered that it would not go into neutral. Thank goodness the discovery was made before I put the transmission back in the car. Found that when I removed the input shaft retaining collar and pulled the input shaft out just a little bit the transmisson would be in neutral. Decided that the problem was the fit of the main shaft into the input shaft. Disassembled the transmission and removed the main shaft. In comparing the end of the main shaft to the one out of my regular 3 speed I could see that the repaired tip of the O/D main shaft did not have the same taper as the regular 3 speed. So I took it back to the machine shop this morning and asked them to grind in the taper. I figure without the taper, when the retaining collar pulled the input shaft in tight there was too much interference with the tip of the main shaft and the resulting binding kept the transmission in high gear all of the time. If nothing else I am getting pretty adept at assembling and disassembling the O/D transmission.

Jim Yergin

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