Chevrolet - Cavalier :: 2002 - Trans Slipping When Shifts Into A Higher Gear

2002 CAvalier 2.2 automatic with 123'000 miles. I was asked to look at this car for a slipping trans problem.

I drove the car about 3 miles and in 1st and Reverse it feels normal, even on a steep hill, but once it shifts into a higher gear the trans slips and you can go only about 15mph.It is shifting, because if you move the shifter into a lower gear while traveling....you can feel it downshift.

There is a code of P0502 Vehicle speed sensor. and there is no Trans fluid visible thru the filler cap on the trans top.

Previously someone else worked on this car for the slipping trans....changed some sensors....but couldn't fix the problem. The owners don't know what parts he replaced. He works for a Tire outfit and I've known him to lean towards used parts a lot.The previous mechanic convinced them that it needs a new Cluster. I presume he means instrument cluster.

I have a feeling that he just threw parts at it hoping that something would stick.

I presume that he replaced the VSS, and it didn't cure the problem.Come to think of it....the code could be from before the other persons work. I should have cleared the code and test drove it again.

I'm looking at dropping the pan, replacing the filter, refill the fluid, and replace the VSS

My questions: Could a instrument cluster have anything to do with the shifting problem.

Is the level of trans fluid supposed to be above the ledge under the filler cap, or is there a "full level" plug in the side of the trans. If he replaced the VSS with a new one....and the fluid level is good....whats my next step.