On 5 Mar 2010 07:20:52 GMT, ddl@danlan.*com (Dan Lanciani) wrote:

In article , writes:

| It's not up to me to watch the news to prove your claims. You
| claimed specifically that a Lexus had been brought to a stop by
| shifting into neutral during runaway conditions. First, on the face
| of it, this is actually impossible to do, because no one has been able
| to duplicate the "runaway" condition. So, the best you could be
| referring to was that it's been proven that a Lexus identical to the
| one driven by the CA highway patrol officer can be shifted into
| neutral when traveling 120mph under full throttle.

I'm sorry if this is a stupid question, but I really don't know:
typically, does shifting an automatic transmission into neutral
actually disengage a gear or does it merely cause the torque
converter to stop transferring torque?

It disengages the drive clutches of the planetary gear sets -
effectively disconnecting the gears.

Let me explain why I ask. I have a 1997 Toyota Landcruiser with
automatic transmission. It also has a (totally mechanical) shift
on the transfer case to select low or (normal) high speed. The
manual says to put the automatic transmission in neutral when you
want to change the transfer ratio. If I follow those instructions
I hear/feel a nasty gear grinding when I try to shift the transfer
case, suggesting that somehow the output of the transmission is
still rotating with at least some force.

The planetarys are still spinning, with some friction dragging the
output around. Much better to shift in park - or come to a full stop,
THEN shift into neutral and shift the transfer case quickly

If I put the automatic
transmission in park then transfer case shifting is smooth and
quiet, though as I pass through the neutral position of the
transfer case I get a warning light that the A/T parking break
is no longer effective. The manual says not to do this, but I'm
not sure why.

Incidentally, there are two solenoid interlocks that can prevent
certain shifts of the automatic transmission but nothing (well,
at least nothing electric) that can stop me from putting the transfer
case in neutral so I figure I'm safe no matter what any computer may
decide to do.

Dan Lanciani
ddl@danlan.*com