I'll describe this symptom as best I can:

When moving at 10 MPH or less, and turning to the left (either slightly
to the left or sharply to the left), particularly when pulling away
from a stop and turning to the left, I get a "shuddering" vibration
that can be felt through the steering column, brake pedal, and floor.
The sound and vibration is also heard and felt by passengers.  And it's
far more likely to start shuddering if I "ride" the brakes lightly
while slowly turning left.

I'm at a loss to describe the sound and frequency.  It's almost as if
the front calipers aren't releasing well, sort of snagging and
dragging.  But I can't imagine why turning left would affect this.

This occurs ONLY when turning to the left. I've tried but cannot make
it happen straight ahead or turning right.

This truck is under warranty, and I am already planning to take it in
for another brake problem (grabbing/shimmying when braking,
particularly from 45 mph or higher).

Question - is the low-speed-when-turning-left shudder a known problem
that is related to the high-speed braking shimmy?  If so, rather than
confuse the service writer with multiple complaints, I may just let
them correct the shimmy (I understand this is a TSB which involves
turning rotors and replacing calipers) and wait to see if the other
problem goes away.

thanks,

Martin