Douglas Frank wrote:
>
> Michael Ferguson wrote:
> >
> > John, according to The Roadster Factory catalog (Glovebox Companion for
> > TR3), you've got it backwards. GL4 is the recommended lube...GL5 is the one
> > with the harmful additive. Hope they're right as I have GL4 in mine! :^)
>
> Now you guys got ME confused! :-)
>
> I was under the impression that GL5 is perfectly OK in the differential
> (it's only the gearbox that requires GL4)-- because there are no bronze
> bits in the diff. Um?
I'm not sure, even though the additives in GL5 are described as hostile
to copper-based parts such as bronze and brass, that the rate of attack
is all that quick. Most differentials use plated brass, copper and/or
bronze parts somewhere, even if only at the thrust washers for the
differential side gears. And yet, our axle manufacturer has approved GL5
for use in their axles supplied to us.
Because of the shape, function and material composition of synchros in a
transmission, however, I'd be leery about GL5 use in that component (new
transmissions on very late-model cars probably are exempt from that
worry, since many of them seem to use molded carbon fiber/epoxy
synchros). For Triumphs, no, I wouldn't recommend GL5 in the trans.
It's also worth mentioning that earlier comments about not using hypoid
gear oil in overdrive transmissions still apply, whether to GL4 or GL5.
While getting some old Triumph bulletins ready to put up on the web, I
ran across one from 1955 which clearly states that hypoid gear oil is
not to be used in overdrives.
Cheers.
--
Michael D. Porter
Roswell, NM
mailto: mporter@zianet.com
`70 GT6+ (being refurbished, slowly)
`71 GT6 Mk. III (organ donor)
`72 GT6 Mk. III (daily driver)
`64 TR4 (awaiting intensive care)
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