Transmission locked up

[Underdoggie]

The other day my son was riding my 75 FXE, I was behind him and all of a sudden the rear wheel locked up as he was downshifting from 3rd to second getting ready for a stop sign. He skidded about 70 feet. The bike hopped the last 15 feet. Scared the crap out of him and his girlfriend. I fiddled with the shifter and finally got the bike to roll again and we got her home and I tore the tranny out of the bike. When I took the shifter lid off I noticed 2nd gear on the counter shaft had two teeth missing and they were in the bottom of the box.

Then I noticed the lock ring that holds 3rd gear on the main shaft was out of its groove allowing 3rd gear to move toward the main drive gear.

It is slightly dished and shinny on one side. I am not sure what forced it out of its groove but am pretty sure it locked up cause it was in two gears at the same time. I'm not an expert but have been in several transmissions. So any ideas on what happened are sure welcome.
The other question I have is the lock ring on the countershaft is referred to as a spring lock ring part n0. 35810-36 and is really like a spring going around the shaft more than 360 degrees. The replacement I got from V twin has the same part number but looks different. It has a gap in it and looks more like the one in the picture I posted of the 3rd gear lock ring. Can anyone tell me the story on that spring lock ring and why I cant seem to find one.
Thanks,

[duffeycycles]

Someone reused the lock ring[freaking no-no]-or they didn't get it in right[freaking no-no]-these are a bitch to remove and install
I see this often by wanna be mechanics[MMI grads!]
The countershaft spring lock that goes past 360deg was aftermarket-they look like the one shown

[Rubone]

I find your issue quite interesting Underdoggie. In '75 I was working for a dealership in Albuquerque, NM. We received a shipment of ten Police units which I set up and sent on to the PD to be put into service. About a month after they arrived one of them locked the gearbox on the Interstate at speed. The officer was able to keep upright for a while and luckily escaped with minor injuries. Upon tearing the gearbox down I discovered the third gear snap ring had come out and the third gear had moved over enough to engage the high/third clutch, locking the box. When I tore the box apart, the snap ring groove in the shaft was machined improperly either by a broken tool or a improperly shaped one. It had a radius on one side which allowed the ring to ride up and out of the groove when under side pressure. After talking to the H-D warranty guys and battling with them over the issue, the police department stated that either H-D replace all the transmissions in the ten bikes, or that they take them all back. H-D squawked but accepted the deal as they didn't want a lawsuit with a large metropolitan PD that had used their products for years. About a week or so later i received a large crate with ten new gearboxes in it. The PD brought the bikes in two at a time and I swapped them out. I was happy to do it as the flat rate was pretty good and I was very fast in those days. No one from H-D ever really answered the questions as to the shaft issues and how many could have gone out screwed up. As we all know, quality control in those days was pretty poor. I doubt it was an issue in all those gearboxes since they were in no way consecutive as per shaft machining, but the factory nor the PD were taking a chance.
Perhaps yours was a brother to the one I did so many years ago. Look closely at the shaft!!

[Underdoggie]

Thanks Robbie for that, I will inspect that main shaft tonight under magnification. It is the original box too. I did take it apart in 1988 to repair a leaking Main seal, as part of that rework I had cotton hone a 4th gear bearing to the original shaft and it is getting a good look tonight because even tho it has run many a mile since 88 I just feel the need to understand why it failed. Locking a tranny at speed would be terrible and I don't want to experience it.
Duffy, I did use a new clip when I did the main drive gear bushing and thanks for the spiral lock ring explanation. I have only been in about 4 trannys and its been a long time.

[Underdoggie]

Oh and by the way Robbie, that is an amazing story, I bet you were damm fast at that after a couple in a row. Back in 75 they probably were still using form ground hi speed steel or cemented and ground carbide to form those grooves, there is a lot of variation in that kind of process.

[Rubone]

Yeah, the cross section profile of the snap ring groove appeared to have been cut with a tool that the corner had broken off of. So it was square cornered on the 3rd gear side but had a distinct ramp/radius on the high gear side. When under load it seemed to have thrust hard against the snap ring and just popped it out. I had spent a couple years in machine shops between custom shops and the dealership which helped a bit in determining the cause. At that point in time H-D was trying to push out all they could. Production had gone from tens of thousands to over 100K plus in a few short years and the push was still on. I saw a lot in the '70s, both good and bad.

[Underdoggie]

Well I inspected the main shaft. I took 3 different pictures, this one looks the best. Both sides of the groove look angled to me. I put the old ring back on and is moves back and forth. I put a new one in the groove and it was tighter but still felt like it moved a little. I think this thing has been trying to get out of that groove for a long time and finally made it.

In this day and age where would one go to get a high quality replacement, I know Cotton has said even some of the good names in the business have so much demand they farm stuff out to Taiwan all the time.

[T. Cotten]

Underdoggie!

There had to be unusual thrust upon the gear to make it kick one way or the other.

And I said what?

....Cotten

[duffeycycles]

don't use import mainshafts uness you like little pieces
http://www.vtwinmfg.com/webapp/wcs/s...102_3296548_-1

[Underdoggie]

Underdoggie!

There had to be unusual thrust upon the gear to make it kick one way or the other.

And I said what?

....Cotten

The unusual thrust could have very well been the two broken teeth from 2nd on the countershaft trying to fit in the space between second and third gear. You told me before that the quality of Jims stuff had gone down hill as his business grew. At your age you probably just forgot. At any rate the lock ring does not fit snug in the groove. That is definitely a problem.

[duffeycycles]

The broken teeth are probably caused by the thrust washer out of position not the other way around

[T. Cotten]

The unusual thrust could have very well been the two broken teeth from 2nd on the countershaft trying to fit in the space between second and third gear. You told me before that the quality of Jims stuff had gone down hill as his business grew. At your age you probably just forgot. At any rate the lock ring does not fit snug in the groove. That is definitely a problem.

Just for clarity, Folks,

Yep JIMS lost quality when they got too big, but I would be surprised if they went to Taiwan for much. (There's always South Korea?...) Haven't needed to deal with them again for years, so I have no clue.

I'm still having issues with my sources as well, so "good names in the business" now means independent cottage industries, not megamart distributors who are most likely to go to the Orient.

And back to mainshafts, I remember a 'USA' Andrews where the splines were not concentric with the rest of the shaft, and it went out of gear when it was banged real good.
Twas many years ago, though. Should have forgotten it by now...

....Cotten

[Underdoggie]

Well, I have screwed around since this happened in March trying to come up with some mystical reason for the lock up but now its time to put it back together. I was thinking about doing it in front of you guys on here. I need to put all the stuff on the table back in the hole in the bike. I'm no pro, just a hobbyist, think there would be any interest?

[painterdale]

Bring it on, John! I'm interested. Dale