<VV> Towing Per the Tech Guide

[Tony Underwood]

At 02:31 hours 07/18/2005, BobHelt at aol.com wrote:
>In a message dated 7/18/05 8:25:41 AM US Mountain Standard Time,
>gyoungwolf at earthlink.net writes:
>
> > I went back to the Tech Guide and found two articles in the Travel and
> > Towing section, pages 3 and 6, by Larry Claypool that say it is 
> only safe to tow
> > PG cars for 50 miles or so at 50 mph or less. The articles state that the
> > problem is heat build up which can causing foaming, fluid loss, 
> hardened seals,
> > and damage to friction surfaces on clutches and bands. I guess we 
> should ask
> > him if he has changed his mind....,
>
>I think you will find that LC was pretty much just reiterating what the Shop
>Manuals say about towing the PG.




The problem here is that the SM doesn't really provide accurate info 
on this.  I've seen a PG Vair towed almost 1000 miles at Interstate 
speeds with hardly a stop other than for refueling and it arrived in 
my driveway just fine, and the transmission was hardly warm.    I 
crawled under it and checked, slapped a palm on the transmission and 
it was hardly warm, no problems.   I've towed other PG Vairs on 
Interstates etc and not stopped for long distances and never had a 
problem at all.    Others have as well.

Was the original SM just making a "blanket statement" regarding 
flat-towing vehicles regardless of transmission type?

On the other hand, a manual gearbox WILL get damned warm while 
flat-towing since the cluster gear doesn't turn and the mainshaft and 
synchro hubs don't get any splash oil... and they eventually will 
heat up.   Been there done THAT too, and they do get pretty hot 
unless that cluster gear turns now and then, to lube the mainshaft

Heat generated in a Powerglide comes mainly from the fluid in the 
converter being churned during slippage within the converter.   No 
other parts in a Powerglide should be generating any more heat than 
what you'd see in a manual gearbox operated normally with splash 
oiling via the cluster gear turning etc.   The vast majority of the 
heat is generated within the converter, not within the transmission 
itself, and even then only during engine operation while the fluid in 
the converter is being agitated.    During towing, the transmission 
gets ATF circulated to various points by the rear pump, no lack of 
lubrication.   The converter does nothing at all unless the engine is 
running or the transmission is towed in gear.    No heat from that corner.

So, the PG shouldn't overheat at all, regardless of how far or how 
fast you tow it.   And in fact, this has been my experience.

*My* experience...  others' mileage may vary.    But to date, I've 
never damaged a PG or even gotten one excessively warm no matter how 
fast it was towed or how far, as long as it remained in Neutral and 
it didn't have any serious internal problems to begin with.


tony..