Re: Towing

[Simon Favre <simon@domain.elided>]

Ahh, touched a nerve, did we? ;=) The thing about towing is that the ring
and pinion are CONSTANTLY in mesh on the wrong gear faces. Yes, those gear
faces come into contact when you use the engine for braking, but it is not
constant by any means. There are a couple of other things to point out. A
ring and pinion is a hypoid gear train. Not only is the pinion below the
centerline of the ring, but the teeth are curved. If the teeth were meant
to be driven constantly in the other direction, they would be curved the
other direction. Lastly, the fact that you are spinning the driveshaft as
well means that the mainshaft of the tranny is spinning inside every gear
wheel without the benefit of having the gears moving the oil around. If it
was my car being dollied, I'd pull the driveshaft for that reason alone.
Pulling the driveshaft, or at least the front section, would also reduce
the wrong-way wear on the diff. Obviously, people have flat-towed and
dollied Alfas before, but I still don't like the idea. I seem to remember
reading somewhere that if you are flat-towing a car without pulling the
driveshaft, you are supposed to stop every so often and start the motor
just to circulate the tranny oil.

JHertzman@domain.elided wrote:
> 
> In AD7-538 Simon Favre writes:
> 
> "The main reason not to tow a RWD car on a dolly more than 100 miles or so
> is that you are causing the ring and pinion to wear on the opposite side
> of the gear teeth. The same goes for the tranny. Doing this can cause
> particles to shed into the oil that will cause premature wear. I would
> change the tranny and diff oil after such a tow. Even with the driveshaft
> out, the diff is still subjected to abnormal wear."
> 
> ?? I would think that the gears would catch the same punishment any time you
> backed off on a downgrade, used engine braking deliberately prior to a turn,
> or coasted, or used free-wheeling, which was fairly common equipment on pre-
> war cars. Granted these are short periods, rather than a hundred miles, but
> would there be that difference in the lubrication, metallurgy, machining, or
> gear design when the engineers know that deceleration will be almost as common
> as acceleration?
> 
> I have flat-towed and dolly-towed Alfas over considerable distances (like 800
> miles) with no ill effects that I know of, and Fred DiMatteo felt no
> compunctions about flat-towing his Junior Z at high speeds over considerable
> distances. In my Milano Owner's Manual, which spends a page on towing cars in
> various conditions with various equipment, there is no sign of concern about
> gear wear; the only mention of dropping the driveshaft is in connection with
> towing locked cars. I question the likelihood of abnormal gear wear.
> 
> Cordially,
> 
> John H.

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