[TR] Calling anyone with transmission rebuilding experience - 2nd attempt, part2

[DAVID MASSEY]

 That looks like the heat treated, hardened  surface is starting to break up.  That is what happened to my layshaft.  Another reason to abandon that mainshaft.  If you have an alternate bearing combination that doesn't relay on that surface for the bearing rollers then the hardened surface is no longer critical.  But this is above my pay grade.

BTW, I misinterpreted one of your previous photos.  The split washers transfer the lateral forces from the synchro hub to the mainshaft but the end result is the same, with a compromised groove surface like that the split collars will fail prematurely.   If you open the grove to clean up the shoulder will the split washers stay in place?  If they fall out you have serious problems.  Even if they stay in place will it increase backlash?  Can you get oversized split collars?  Make shims?  All this is above my pay grade.
 
Dave 


 
 
-----Original Message-----
From: aribert neumann <aribertn at gmail.com>
To: triumphs at autox.team.net
Sent: Sun, Mar 19, 2023 6:52 pm
Subject: [TR] Calling anyone with transmission rebuilding experience - 2nd attempt, part2

Next question - my (new) replacement main shaft is oversize in a couple of places.   The diameter under the 2nd & 3rd gear bushings (I have opened up the bushings to only have a light interference fit).  Worst is the diameter under the rear bearing.  I can install the bearing but I have to hammer it ***hard*** to get it to fit on the shaft - can't be good for the bearing - guessing I might change the inner race diameter a miniscule amount.  I'm thinking of sending this main shaft back to Spitbits and reusing my old main shaft.  I have cleaned up the groove for the split collars on my lathe.  The other damage on the shaft is on the nose where the cage bearing rides in the input shaft - this damage is only on one side of the shaft and only on half of the bearing surface (fore/aft).  I am already going to replace the cage bearing with a bearing bronze bushing since the surface inside the input shaft pocket is showing wear also.  The max amount of surface missing on the nose of the old main shaft is 0.003 in diameter.   Images:  exploded view from Bentley  manual, nose of the old, worn mainshaft

Your thoughts and suggestions please - off in digest mode awaiting your responses.  Trying to formulate a new plan of attack for Monday morning.

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