2005 Monte Carlo SS 3.8 S/C 158,624

Ever since I bought the car with 127,xxx miles the car did not feel like it shifted right. I ignored the problem because it only shifted hard when I was barely touching the throttle, I mean to be expected with a 20 year old car. Now the car sometimes feels as if its trying to find the gear its supposed to be in. Delayed but relatively smooth shifts are common while unexpected very violent shifts are rare but do occur. I have no clue where to start. The car has now 158,xxx miles. Has a check engine light that was checked while back that was a sensor (drove fine for almost a year with the light on). ABS and traction control lights are also on. Today I pulled out of a inclined T intersection and the wheels were turned slightly past 45 degrees. The car was fine until about 2200 rpm in first gear and completely revved out and lost the gear, I had enough momentum to straighten the car and once the wheels were straight it shifted from 1st to 2nd a little hard but what I would consider normal.

 

How is the fluid level?

 

When was the last time the fluid in the Trans was changed, this should really be don about every 60K and if it was never done this would be a good start point.

 

Was low.. dropping the pan this weekend and replacing filter. We will see if that helps