Gearbox/clutch drama

Selector drum is undamaged. The end of the channels in the first pic is the 5th gear position.






....the last pic stops are first gear
 
Short story is every tooth on 3rd gear is chipped on the output shaft. Besides the tooth chips the only debris in the housing are metal filings. There's minor damage to 4th gear input and output sprockets but nowhere as catastrophic as 3rd. All other transmission components appear undamaged.

Looks to me like 4th and 4th were playing happily and output 3rd came over for a chat with input 4th who tried to include both the outputs in the same conversation....still baffled as to how it all happened though. There are no obvious failures of circlips or bearings or the like
 
Rocket Scientist said:
Great pics ! Thank you for sharing your tragedy with us. (somehow that just doesn't sound right)
Click to expand...
Your welcome Fred .. I hope it helps others get an idea of what's going on in their own machines. They maybe made of tractor parts and cheese but they are a very simple machine to work on.

I'm a hero at the triumph shop...they haven't seen damage like this on a post 2009 R3 transmission
 
I haven't started dismantling the shafts yet but both clips on the output are exactly where they're supposed to be....interesting idea though.

The dealer I visit has replaced a ****load of 2nd gears but never a 3rd and reckons the only way this damage could have happened is through continuous hard shifting and a circlip coming loose/breaking
 
First pic is hard to see but the circlip is visible through the dogs. Second is clear enough
 
Since all the cir-clips are present and in their grooves I would like to know about the shape of the splined bushings that go in the ID of the fourth and third output gears. In the old days they were a splined bushing with a splined washer on each side of the gear stack somewhere in 08 Triumph changed them to the splined bushings with the splined flange attached. I am curious if yours is the same or if they made further changes. I to like Fred appreciate the pictures. Trouble shooting a catastrophic failure can be quite the brain teaser.

I am still amazed at the gap between fourth and third gear output side. its like the cir-clip moved or a thrust washer gone or movement of the shaft from thrust. I agree third gear was the main culprit. One thing to remember all gears are always in contact in the transmission. On the output shaft only fifth gear and the helical out put are splined to the shaft. The helical is stationary as it is held the the shaft by a nut on the end so with the two bearings have a split ring around then so the stay stationary in the engine case. With the spacer , C washer and the flat washer between them and the nut on the helical gear tight the shaft does not move forward or backwards in the engine case. I have seen the nut loose which allows the helical gear a little slide movement on the shaft. This slop turns to shaft movement to to the thrust developed at the mating helical gears. (which is why most helical gears have a helix angle of 20 degrees or less to keep thrust in control. Anyway On the bike I seen the thrust pushed the shaft forward enough to move the front bearing deeper in its bore. This created a gap like what you have between 2nd and 4th out put. on up from and the thrust washer right after 1st gear out put shaft would drop off the diameter it was supposed to ride on (the gear diameter) and it would drop down onto the bearing diameter. Since the ID was so large on the smaller shaft area, depending on how hard you ran the bike would change the shifting ability. By this I mean if enough thrust was presented and the went forward it would pinch and grab the thrust washer which would make it run out and interfere with dogs catching the gear. So if the shaft did not creep forward then were back to how did the slop get between 3rd and 4th gear output. which was enough to allow 3rd gear output to slide out of mesh with 3rd/4th gear that is splined on the input shaft. Once they became out of mesh and then tried to line back up with no synchronization catastrophic failure occurred. sending gear teeth flying around to jam other stuff or just be a general nuisance to the other components.

And that's what we need to figure out how third the two third gears came out of mesh.
 
mr hunt said:
First pic is hard to see but the circlip is visible through the dogs. Second is clear enough
Click to expand...
mr hunt said:
First pic is hard to see but the circlip is visible through the dogs. Second is clear enough
Click to expand...
@mr hunt
somthing is not right there I am looking at a complete assembled shaft and there is not way to view that much of the cir-clips one or both of them has to have moved. I wish you were not on the bottom of the world this long distance diagnostics stuff sucks.

Both cir-clips on them gears should not be out so far that you can see them past the face of the gears. let me copy you picture and also take one of the shaft I have.
 
The output helical nut seems to be tight enough...I get what you're saying about the slop developing. I'll put back in the case tomorrow and reconfirm.
First thing in the morning I'll get some pics of the bushings etc but right now Mrs Hunt requires my attention .... it's bedtime here
 
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