On Thu, 5 Jun 2003, Sally or Dick Taylor wrote:
> Gary---I bought a gallon of StaLube 80/90 gear oil about 10 years ago
> that read: .....GL5....recommended for manual transmissions...... and
> supposed to be a replacement for GL4. OK, oil companies are always
> upgrading their motor oil. I recall needing oil with an SE rating when
> the car was new. Now it is something around SG. Anyway, I've been using
> the GL5 all of this time. I'm not recommending it, but whatever the
> negative effects are, it's certainly slow to show up. There's at least
> 100,000 miles on this unit since the "modern" stuff came in, still
> reasonably silent and shifting well. Less brass in the later trannies??
Well, the later trannys in fact do use less brass. In the '75 and '76
trannys, the mainshaft bushings are steel. The TRF parts Vol 1 inplies
that TR6's starting CF12500 used steel. I have found so far that this is
not true for my car which is CF14111 - I have no idea where the cutover
date is. In fact, after having built at least 10 TR6 trannys, I still
haven't taken apart one with the steel bushes. This is mostly because the
latest TR6 trannys "got it right" and they seem quite robust indeed. This
is not to say that later trannys won't break - they will if abused - but
the steel bushings hold the mainshaft end-float for a good, long time
(unlike the brass ones that seem to need rebuilding more often due to top
hat bushing failure).
However, all big TR trannys use brass/bronze synchros. So these will
degrade due to the high sulphur content of the GL5 lube.
I will reiterate that you must use GL4 in your tranny and diff unless you
know it not to contain brass parts. I've had all my TR6 trannys and diffs
apart - they all have brass. I use Redline MTL in the trannys and MT90 in
the diff. Actually, I use Mobil 1 gearlube in the race car, that has a
Quaife (and the innards are all steel or aluminium).
I will also point out that many modern-ish cars require GL4 lube. One
source used to be VW dealers (because they used brass/bronze). GM sells a
funky tranny lube for synchromesh transmissions too - this stuff looks
like ATF. You can use that. The point is - when you go to buy lube, ask
around and if the seller or advisor says "GL5 is better than GL4", kindly
thank them for the advice and then take your $$$ elsewhere. And if you
settle on some strange concoction (like Redline MTL) make sure you stow
some in the boot when you go on a long trip, because should you discover
that you need some, chances are that you won't find it on the shelf on a
Walmart in "Anytown, USA".
> Dick
regards,
rml
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