>Laycock says, for ALL of their LBC overdrives, to use motor weight oil, in
>the 30-50W range. (20w50 is the cure here)
>In spite of the fact that yes, a normal later TR box uses 90w, if you insist
>on putting this into an overdrive trans., you WILL be eating OD parts for
>dinner!
>The reason for this is that Laycock overdrives have many small parts and
>orifices that are designed to be lubed by a relatively light oil eg: 30w
>range. The 90w simply cannot get into the small oil passages with sufficiant
>volume to provide adaquate lubrication. Hence, premature overdrive failure!
Um, did you read the messages here that stated (correctly) that
80w90-weight gear oil is basically the _same_ viscosity as 20w50 engine oil?
The biggest difference is in the additive package, most of which doesn't
really matter a great deal to a trans or OD. I suspect that either a good
20w50 _or_ a good non-EP 80w90 would be fine for an OD, and that most of
the arguments boil down to religion and/or superstition. Too bad laycock
isn't around to ask (I think). Any lubrication/oil engineers around here?
Perhaps in British-Cars?
>On the otherhand, the TR box is perfectly happy with a good grade of 20W50
>oil, it will lube it well, last a long time, and wonder of wonders you will
>also find it shifts smoother!
Engine oil should work there, though it seems unlikely that it would
shift significantly better. There would be some difference, so it's possible.
> The only caution here, and it holds true
>anyway, is that you may want to change the gearbox oil at the recommended
>intervals instead of the typical and tradition interval of once per
>millenium.
If you have an OD, change the oil regularily. Without an OD - it's
not a major deal. I did have the oil changed when I happened to have it in
being aligned (for the first time in around 7 years). Didn't affect anything
I could tell - still whines in all but 4th (I've been sitting on a rebuild
kit for about 5 years for an opportune moment or failure).
--
Randell Jesup, Scala US R&D
Randell.Jesup@scala.com
Ex-Commodore-Amiga Engineer, class of '94
#include <std/disclaimer>
|