Hi Ed,
I know (from experience) that BMC designed cars use a 20/50 engine oil in
the gearbox. I just checked this in an MGB
manual, so it's not my memory playing tricks!
I have heard it said that EP90 gear oil is heavier than is ideal for the
Laycock overdrives - like the BMC gearboxes, they
were designed to use lighter oils. Unfortunately, I don't know what effect the
lighter oil would have on the Standard-Triumph
gearbox.
I will mention (on a similar theme) that you should use a gear oil to
API-GL4 standard, NOT API-GL5. The latter oil,
(which seems to be more generally available) contains active sulphur components
which will over time attack the yellow metal
components in the gearbox,
Regards,
Bill.
Edward Hamilton wrote:
> Forwarded to the Triumph list in the interest of gaining additional
> insight.
>
> Best regards,
> Ed Hamilton
>
>
>------------------------------------------------------------------------
>
> Subject: Slipping O.D.
> Date: Fri, 29 May 1998 16:42:51 -0400
> From: Edward Hamilton <hamilton@ptd.net>
> Organization: WRI, Inc.
> To: Spitfire Mail List <spitfires@autox.team.net>
>
> Prior to removing the tranny and replacing the clutch on my '80 Spitfire
> (about two months ago) the overdrive unit seemed to work perfectly.
> Until last night, I thought I had a slipping clutch -- which I'm now
> convinced to be the overdrive. While removed, the only thing I did to
> the tranny and overdrive was to drain the fluid (no idea what was in
> it), clean the filters and top it off with the specified 85-90 GL/4 gear
> oil.
> I've spoken to a reported guru of gearbox/od units who tells me he never
> puts 90 wt. gear oil in them -- too slippery and can cause the unit to
> slip when in direct drive. Says he has always put straight motor oil in
> -- 50 wt. His suggestion to me is to drain the unit and fill it with
> regular automatic transmission fluid, run it for a few miles and drain
> again -- the A.T.F. to help clean out the 90 wt. gear oil. Then to fill
> the unit with straight 50 wt. motor oil. He offered this suggestion
> prior to my sending the thing to him for a rebuild, so I believe he has
> my best interest at heart.
> Would like to know if any other listers have had this type of problem
> and/or comments regarding the above. In other words, what do you guys
> have in your gearbox?
>
> Best regards,
> Ed Hamilton
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/ \ Total Triumph Enthusiast
__ __________________ __
/ \ ______ ______ / \ 1959 Herald 948 Coupe
\__/ \ || / \__/ 1960 Herald 948 Saloon
| A \____||____/ A | 1960 Herald 948 Saloon Export
| = H H = | 1964 Herald 1200 Saloon
=====U==============U===== 1966 Herald 1200 Convertible
\________________________/ 1970 Herald 13/60 Saloon
| | | | 1959 Standard Atlas Pickup
|_| |_| 1972 Spitfire MkIV
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