[TR] Problem solved - not totally sure how

[Rye Livingston]

How do you like that title?  Somewhat seriously, the overdrive issue is fixed, but they aren't quite sure how/why.  

This is the issue of overdrive dropping out when under load during acceleration like an automatic transmission.  They took the transmission out of the car again, second time, and took it all apart again, for the second time.  The overdrive was completely dismantled and inspected part by part, piece by piece, everything looking absolutely perfect by Dave, and Jim who is a British transmission specialist. Jim was holding the tapered cone gear I think it's called, which has the clutch material around the outside of it, which fits into the sun gear, I think I have the correct names for these, anyway, when he manually pushed the two together as they would engage, there was the slightest movement in the fit.  They showed it to me and there is about 1/16th of a wiggle.  Both Dave and Jim said when looking at this, it's so slight they both felt it should work and not be an issue.  But they couldn't find any other issue so he dug through his inventory and had one from his new old stock, manually put that one in the sun gear, no wiggle at all.  They put it all back together and bingo, shifts perfectly.

The "not sure why" part is because they both feel that slight gap shouldn't have caused the problem, and wonder if there is some other fluid that could have soaked the clutch material causing it to slip.  I don't remember the name of what it is, but his example should resonate with some of you.  In a particular model of Jaguar the differential binds badly and makes some bad noises.  In with the differential oil there is some sort of fluid that by design allows it to bind less and it works perfectly and no bad noises.  If that fluid was somehow added to the oil in the OD it would cause it to slip, and would be undetectable to the touch of the clutch material when dismantled.

A few of you responded that the clutch was slipping, and you were right, but it wasn't because of low PSI keeping the OD engaged.  I want to be sure and make the point that British Motorsports stood behind their work rebuilding the transmission, and the only charge to me was for the tapered cone gear.  

Bottom line I'm thrilled it's resolved and with the strong rebuilt engine, the car is very quick and a blast to drive.  Now to start on my list of smaller projects getting the car ready for Triumphest this fall in Ventura, CA.

Rye
Activities Director
Triumph Travelers Sports Car Club
1960 TR3A
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://autox.team.net/pipermail/triumphs/attachments/20160722/6bb0c1c2/attachment.html>