'89 200 2WD 3 spd Auto Trans Intermittently poor Shifting

[shawn]

I have just completed a marathon session taking care of much deferred
maintenance in preparation for a 1,000+mile drive from San Diego to Boise. I
am moving there.  (I know, I know, why would anyone make that move.)  I
drive out Sunday morning.

I haven't had shifting issues before and I've never had the transmission  or
final drive  serviced.  I called a quickie shop once and they wouldn't touch
a car with over 120K miles, mine has 150K.  I called the dealer today and
they said it never needs routine service and
furthermore they can't look at it for 2 weeks.

I don't think anything I did could affect shifting, but here is the list:

Timing Belt
Water Pump
Idler Pulley
Front Main Seal
Front Cam Seal
AC/PS/Alt Belts
RH/LH Motor Mounts
RH/LH Transmission Mounts
Oxs Sensor
Fuel Injectors X 5
Fuel Filter
Oil Change w/ Filter
Air Filter
Radiator mounts

The two issues that have arisen:  Left home, car cold, wouldn't shift from
2nd to 3rd would have run up to (and beyond?) redline.
This morning put the car in reverse and it took a couple seconds to "catch".
The issues seem to spontaneously resolve after the transmission warms up.
The fluid when measured warm, not hot, was half way between add and full.

Is there any easy way to diagnose my problem or an "AT Tune-up in a can"
that I can add to the fluid?