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Hi all,

My 75 CL360 (only 3,500 miles on it) stopped being able to shift up in to second after running great for a few weeks. I bought it last month from a guy who bought it as a restoration project from the original owner, who had it in dry storage for 40 years. I posted earlier about the shifting issue, but have since opened up the right crankcase and exposed the shifting mechanism and drum to see what the source of the issue is. It seems to be something in the transmission and not in the gear shift mechanism, as the problem persists when taking a screwdriver to the shift drum and turning it manually. It won't shift except when I turn the rear wheel in to a specific position, and even then it feels like things are not settling correctly. I took a video of this:

https://vimeo.com/218319466

I would really appreciate any ideas of what could be going on. We plan on removing the engine and opening up the transmission to find out what the issue is. Thank you!
 

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Hi all,

My 75 CL360 (only 3,500 miles on it) stopped being able to shift up in to second after running great for a few weeks. I bought it last month from a guy who bought it as a restoration project from the original owner, who had it in dry storage for 40 years. I posted earlier about the shifting issue, but have since opened up the right crankcase and exposed the shifting mechanism and drum to see what the source of the issue is. It seems to be something in the transmission and not in the gear shift mechanism, as the problem persists when taking a screwdriver to the shift drum and turning it manually. It won't shift except when I turn the rear wheel in to a specific position, and even then it feels like things are not settling correctly. I took a video of this:

https://vimeo.com/218319466

I would really appreciate any ideas of what could be going on. We plan on removing the engine and opening up the transmission to find out what the issue is. Thank you!
Just so you know - despite these transmissions being "constant mesh", meaning all gears are always engaged tooth-to-tooth with another gear on the opposite shaft, they don't work like car transmissions that have synchronizers. There has to be some amount of gear/shaft rotation, whether generated by moving the rear wheel or starting the engine/easing the clutch out, to allow shifting properly. During upshift or downshift, the gears engage with the next position by engagement "dogs" on the sides of the gears to connect one freewheeling gear to another that is locked to a shaft for that particular gear selection (1st through 5th or 6th in your case). Trying to go trough the speeds from top to bottom or vice versa without wheel or shaft movement won't work and forcing it to try to do so can lead to bent shift forks. You'll get a much clearer picture of all this once you get the trans apart and watch the components interact with each other. As for what is causing yours to be difficult, it's hard to say without disassembly but since it's been sitting a very long time, I suppose it's possible that a bit of rust has built up on some of the moving parts like the shift drum and/or forks, since they reside above the shafts and the oil runoff would leave that area first when sitting.

EDIT: I just watched your video - notice that when you're turning the rear wheel and trying to shift the trans, the mainshaft is turning as well - if that were still attached to the clutch and held still by the engine, you would probably have no issues going through all the speeds. I'm not sure there is anything wrong with it based on what I saw. The mechanism seems to sound clean and clicks into the next speed once the dogs are aligned. Try leaving the rear wheel alone (or holding it still) and turn the mainshaft while trying to shift, see if it seems any better.
 

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Nice write up, nothing to add.
Very Very expensive 'race car' transmissions are now made with 'motorcycle' constant mesh transmissions (WRC since the mid-late 80's)
 
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