2000 ford escort jerking transmission cause?

I have a 2000 ford escort zx2 automatic with
152000 miles on her, I just replaced a bad
alternator and serpentine belt, now I'm
having issues with what I'm guessing is my
transmission. I hope you can give me a
direction or advice. My fluid is at the right
level and not too dark, maybe a little high,
barely. I was using cruise control and I
tapped the brake to shut off cruise control
and slow down, and the car dropped out of
fear and revved from 2700 rpm to 4-5k, and I
had to slow down and go back up to shift up
again. Now the car has a slight tugging when
shifting up, and when I shift from park to
reverse or drive it has a slight jerk to it.
Today when I cold started my car, it revved
up to 4-5k when I pressed on the brake to
shift into reverse, then had a rough shift
between reverse and drive. Any ideas on
what this is?