Backdriving a hypoid gear during towing

[JHertzman@domain.elided]

It was comforting to see Joe Bender-Zanoni agreeing with me about the risks of
towing- I don't mind being wrong (particularly if it leads to an illuminating
discussion) but it is sometimes nice to not be alone.

I had not been concerned with heat under a continual light backloading, , but
had found Simon's "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" rather alarming, conjuring up visions of magnetic drain plugs festooned
with shards of the arse-ends of precious gears. This would be independent of
duration, I would think- if one downshifted for maximum engine braking there
would be heavy back-loading of short duration, and brutal abrading of the
rears of the poor teeth, if Simon's premise is correct.

Joe B-Z does not address Simon's second point, "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.- - - - 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". Sounds credible.
But most of my flat-towing has been with non-running cars.

Any other input would be very welcome at my end-

Sincerely,

John H.
Raleigh, N.C.

------------------------------