[Healeys] Dave Dougan's overdrive part 2

[WILLIAM B LAWRENCE]

You can use heavier oils in the overdrive. As a matter of fact Triumph
specified 90 weight GL4 in their trannies, and therefore must have considered
it safe for their overdrives which up to about 1973 were identical to ours.
Because Hypoid, or EP oils contain additives to protect gears which have a
slipping or rubbing action, such as hypoid form gears, I was taught that using
a Hypoid or EP oil in an assembly that requires friction to function, such as
a synchronizer or wet a clutch would cause them to malfunction because the EP
additives would eliminate the required friction. Triumph must not have gotten
that message because their specification for the TR6 calls for a Hypoid or EP
oil and their trannies and ODs seem to function normally.
Bill Lawrence

> Date: Sat, 14 Nov 2009 15:57:34 +0100
> From: coudesluijs at chello.nl
> To: lapierrem at sbcglobal.net
> CC: healeys at Autox.Team.Net
> Subject: Re: [Healeys] Dave Dougan's overdrive part 2
>
> Redline MT90 can be used but is not easily available, at least not in
> the NL. There are other similar oils (GL-4), some synthetic others
> mineral: Quaker state HP or Synquest, Millers EP, Shell Spirax GX,
> Texaco Multigear MTF and others. Practically all are hard to find and do
> not add much if anything at all in normal applications to simple 20W50.
> These oils do not contain S or Cl containing compounds to do damage to
> brass baulk rings or other Cu containing metal parts.
> Kees Oudesluijs
> NL