> I was reading some of the topics on the Quantum Mechanics
> website, and saw
> that John Esposito recommends using non-detergent 30W oil in the OD and
> gearbox rather than the TR-specified 90W hypoid gear oil.
Triumph actually made conflicting recommendations, I've seen an earlier
factory Technical Service Bulletin that specifically forbid using "hypoid"
(ie gear) oil in overdrives. And Laycock, the maker of the overdrive,
always recommended motor oil.
The legend as it was passed to me is that around 1960 (about the same time
as the BL merger), Triumph/BL decided they were having too many warranty
returns for the thrust washers in the gearbox. They apparently decided it
was better to risk returns for OD clutches (which is why Laycock said not to
use gear oil) than thrust washers, and so changed the recommendation without
approval from Laycock.
> His arguments sound convincing, and since a couple of listers yesterday
> recommended him highly, I thought I'd make the changeover. Has
> anyone done
> this, or have any opinions on its merits?
I use Valvoline 20W50 Racing (motor) oil in mine. Although not
non-detergent, it is low-detergent. Best of all, it has high levels of a
zinc "anti-wear" additive that actually works like an extreme-pressure
additive, but is apparently harmless to the OD clutches. It also has none
of the sulfur-based extreme-pressure additive that can corrode copper and
brass components (and is found in gear oil, even GL-4). It's been
extensively tested by some people I trust, including Herman (who rebuilt
both of my overdrives). Ken Gillanders at British Frame and Engine tore
down his OD gearbox after 5 years on the stuff, and said he found no
significant wear on any component.
Note that the factory recommended 50 weight (rather than 30 weight) in hot
climates (at least for TR3, I assume TR6 is the same), and I do live in a
hot climate. The multi-weight oil seems to let the gearbox shift better
when cold than straight 50 weight does.
Randall
59 TR3A TS39781LO :(now totaled :(
56 TR3 TS13571L next project
71 Stag LE1473L daily driver wanna be
63 Sports 6 HB7826LCV rustoration project for sale
57 TR3 TS21731L "someday concours restoration project" rusting quietly 2000
miles away
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