[TR] Info. on Towing a Spitfire

[Dave Massey]

It the engine isn't turning the lay gears aren't turning and there is no
distribution of the gear oil.  Also the main shaft cluster isn't turning
either (since they are meshed with the layshaft) but the main shaft (which is
connected to the output flange) is.  So the main shaft is spinning in the
stationary main gear cluster and without lub the bushings will suffer.  Also
note that even if the car is stationary as long as the engine is turning and
the clutch is released the layshaft cluster gears are turning distributing
oil.

There are a lot of variables.  What type of oil is in the transmission.  What
is the ambient temperature.  But the most important variables are how long is
the two and how recently was the engine run (gear oil circulated) before the
tow.  I have also heard that you can overfill the transmission to obviate the
problem.  If you fill the transmission to the point where the main shaft is at
least partially submerged you will probably be fine.  But standard fill levels
are well below this point.

I had a transmission fail after a 50 mile flat tow.  It didn't fail straight
away but I believe it is the result of the flat towing.  The failure mechanism
is legit.


Dave Massey






-----Original Message-----
From: Mark Hooper <mhooper at indiefilmnet.com>


I've often wondered about these dire warnings.

During towing in neutral (or deceleration), with the rear wheels turning,
isn't
the layshaft gear assembly (sitting in a pool of oil) turning all the time?
And
since it is meshed with some of the main gears above, wouldn't that transfer
some oil constantly to the main gears?

Just wondering again...

Mark

1972 TR6