I used 50 Wt Valvoline Racing Oil in my race car transmission for nearly 20
years without a problem (both overdrive and non-overdrive). In my street
cars I use EP80/90 Valvoline gear oil, again, without any problems. In
fact, in all the years of using TR overdrives (TR-3/4) on both street and
track, I have never had a mechanical failure. I have had a couple of
electrical failures related to the on/off switch or the solenoid - but
these are external to the overdrive unit itself.
-----Original Message-----
From: Jim Hill [SMTP:Jim_Hill@chsra.wisc.edu]
Sent: Wednesday, February 09, 2000 6:04 PM
To: 'fot@autox.team.net'
Subject: Gearbox Oil - Overdrives
During the recent discussion of using overdrives on Triumph vintage racers,
the question of the proper trans/OD oil came up. Bill Dentinger wrote:
>Mike Belfer always used KENDALL THREE STAR.
>Apparently the two clutches in the overdrive
>would each prefer a different weight gear
>lube. The KENDALL THREE STAR was a sort of
>compromise between the two. This too, Mike
>got via Group 44.
Today the following note appeared on the Big TR list. Any comments?
>1) The maker of the overdrive, Laycock,
>specified motor oil, and issued a specific
>warning against using "hypoid" oil in the
>overdrive, as it would "damage" the clutch.
>2) Triumph originally followed Laycock's
>recommendation, and specified motor oil for
>both OD and non-OD gearboxes for the TR2/3.
>This is in the original TR2/3 . . . manual.
>3) Apparently around 1960 . . . Triumph changed
>their recommendation to GL4 grade gear oil.
>This was apparently in reaction to some gearbox
>failures . . . and in contradiction to Laycock's
>recommendation, which never changed. All of the
>other car makers using the Laycock overdrives
>(MG, Austin, Volvo, etc.) still recommended
>motor oil.
>4) Conventional GL4 gear oil does contain a
>sulfur-based "extreme pressure" additive that
>can, under certain conditions of high heat
>(and pressure ?), break down to form sulfuric
>acid, which will attack the brass synchro
>rings, thrust washers, etc. found in the TR
>gearbox. However, it's not clear that these
>conditions exist anywhere except on the race
>track . . .
>5) . . .
6) According to Redline, their synthetic GL4
>gear oil (Redline MTL) does not contain the
>sulfur additive, as their base oil meets the
>EP requirements for GL4. However, there have
>been other problems reported from the race
>track with using MTL (it apparently does not
>allow enough friction for the synchro rings
>and the gear detents to work properly). Again,
>some people use it with no problems.
>7) Ken Gillanders at British Frame and Engine
>has been using Valvoline Racing 20W50 oil in
>several OD transmissions, both on and off the
>race track, for some 15 years now, and has seen
>no problems related to the oil.
>The racing oil contains high levels of a
>zinc-based "anti-wear" additive that also give
>it extreme pressure properties far better than
>the motor oil of the 60s. His personal TR2 has
>been torn down several times to inspect for wear,
>with none found.
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