There seems to be an idea that lubrication in a standard tranny is based on
a pump concept on this list lately...An automatic tranny has, by necessity,
a pump system which can be damaged by setting the trans in neutral and
towing, as then the pump is inoperative. With a manual, usually the normal
fluid level does reach the upper gear/shaft sets enough that they are
partially in the gear oil. These gears turning provide the required splash
to lubricate simply by spinning. The fill level in a Spitfire/Herald tranny
is sufficiently deep to accomplish this. Everything spinning will lubricate,
everything not spinning will get wet anyway. They do lubricate properly when
towed. Just everything is not in operation as would normally be the case.
(take the top off the filled tranny sometime and look in- if the tranny is
out of the car, spin the output shaft by hand, and watch the oil inside...)
I have towed manual transmission vehicles (particularly jeeps, which have
the added problem of a transfer case) many times, on distances up to 1,000
miles each way, on their own tires with nothing done other than to insure
the transmission was out of gear. I have had no ill experiences due to this
method. The main thing is to top up your trans- as it should be anyway.
Having said that, I wish to mention that I prefer to tow with a full
carrier- it is safer for the vehicle(in the way of accident damage
reduction) and easier to maneuver than on its own wheels, as you now have a
centrally supported short wheelbase in tow, rather than a spread wheelbase.
Scott
----- Original Message -----
From: "Randall Young" <ryoung@NAVCOMTECH.COM>
To: <triumphs@autox.team.net>
Sent: Thursday, July 26, 2001 5:55 PM
Subject: RE: Towing TR3
> Bill :
>
> It's OK for short distances (say less than 50 miles). Beyond that, you
> should disconnect the driveshaft, or else fill the transmission to
> overflowing with oil (and drain afterwards). The issue is that the
> transmission does not lubricate properly when the input shaft is not
> turning. Basically, it's normally lubricated by having the countershaft
in
> the bottom (which runs down in the oil) throw the oil all over, which
lubes
> the mainshaft as it runs back down. But, since the countershaft is geared
> to the input shaft, it doesn't turn while you're towing. The bearing
> between the input and output shafts is usually the first thing to go , but
> there are also 3 gears that turn against the output shaft on simple
> bushings.
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