[TR] OD lubrication

[John Macartney]

A point or two on this general thread that I don't understand.

Is there anything intrinsically wrong in using an 80W/90 gear oil as recommended by the factory? 
I've always used it in the Triumphs I've had down the years and with no problem at all. What are the 
benefits (proven or otherwise) of using a lighter weight oil? Is it to enable faster changes - or 
what?

With regard to engagement, some overdrives 'slur' into work, others engage with a mighty thump. Am I 
reading here that users prefer the violent to the more gentle? If so, then the 'thumper' on engaging 
is putting a strain on the engine as it somehow has to suddenly lose some 500-750rpm and the 
flywheel needs immediate slowing. It's different on dis-engaging as an extra 500-750rpm has to be 
found and its all the moving parts from the tyre tread forwards to the engine that does this - wheel 
splines, diff gears, diff nose piece, hardy spicers, gearbox, clutch, flywheel, crank and conrods 
suddenly get accelerated. It's not surprising there's a jerk!

Maybe I've been plain lucky because all my overdrives have been of the 'slur' type and I wouldn't 
have it otherwise. Perhaps it's my own driving style but with or without overdrive I can't stand 
jerkiness or transmission snatch, so I always match engine speed to roadspeed as closely as I can on 
down changes. 'Dipping' the clutch to achieve the smoothness I seek is usually the only way to get 
what I want but even so, it can be done quite fast. Fred Thomas once told me he thought I drove an 
overdrive car differently to others he knew and to this day, I'm still not sure what he meant :)

Jonmac