[TR] OD Oil

[Randall]

> So my question.  I've forgotten whether it was non-detergent. 
>  I suspect so,since wouldn't that give it more grip????

Thing is, the factory switched from recommending motor oil to specifying
GL4.  Seems to me they must have had a reason for making the change.

Ken Gillanders (formerly British Frame and Engine) looked into the reason
for the change, and was reportedly told by an ex-factory engineer that they
were having trouble with premature failure of countershaft bearings/thrust
washers.  They felt the EP additives in the GL4 would help protect the
bearing surfaces.  Evidently it worked, because they continued to specify
GL4 through the end of TR6 production.

I can't say whether that is true, but I note that John Esposito also
acknowledges it as a problem on these gearboxes, and offers to sell an
(expensive) conversion to stronger bearings.

His post about GL4 being too thick makes no sense at all to me.  Even when
the factory did recommend motor oil, they specified 50 weight for temps over
70F.  50 weight is actually thicker than 90 (at the same temperature)!
(They are rated on different scales, which deliberately are offset from each
other.  No such thing as 50 weight gear oil, nor 90 weight motor oil.)

-- Randall