so I've been reading through a lot of posts.. here included, but can't seem to find anybody else with the same problem I'm having.
At first, the problem was mild.. driving down the highway, regardless of speed, the RPMs would randomly jump up anywhere from 200-500 RPM, then drop back down.
As time went on, it started getting worse.. the worst being it not shifting worth a crap. I would have to floor the pedal then let off, just for it to shift into the next gear. A couple times it shifted so hard, it made the wheels squeak. Then, when attempting to put it into O/D, the engine would just rev... as if I just put it into neutral.
Well, I got to looking into things, and thought maybe the TPS was bad, since it does have to do with the tranny shifting. That didn't help...
So I drained all the fluid today, replaced the filter, cleaned the pan (a mild layer of black, most likely clutch material) but no real chunks of metal or anything.
Well, after replacing the fluid, now it doesn't seem to even want to shift past 2nd gear. Even manually, it goes from 1-2 fine, but when I go from 2-D, it still doesn't shift, even at around 3000'ish RPM. And I even tried flooring it, and after I let off the gas, I put down on the gas again and it just revved, and seemed to take a second to get back into gear.
What is the possibility of this being the Transmission Range Sensor? What else should I look into?

Thanks,
Jeremy