[net.auto] 4 Speed Automatic 85 GM transmission

mls@harpo.UUCP (03/18/85)

I have an 85 Buick Park Lane that I bought April 84.  During the
summer it developed a vibration problem at 45 in speed3 and around 55
in speed 4.  The vibration started if I applied a slight amount
of throttle on a small grade the front end would vibrate.  If I pushed
further the vibration stopped.  I assume at that point the lockup on the
torque converter was removed.

Lat fall the dealer fixed the problem.  The gas mileage decreased
and the shifting between 3 and 4 gears was extremely smooth.  I determine
that the way the dealer fixed the vibration problem as not to allow
the torque converter to lockup.  I am presently returning the car to the
dealer.

Has anybody had any similiar problems?
The way I determined that the converter was not locking, was to
attach a lead to the TACH connection on the distributor and bring
it in the car and wrap the lead around an AM radio.  I got an
audible indication of the engine speed.  At 50 I varied the throttle
slightly and heard the pulse vary without a change in speed.

Irv McNair
ATT Bell Labs  Whippany