Transmission problems. Can anybody help?

Hi, new to the forum, hoping to find some help here. Here's my problem. I have a 00 Grand Prix GTP, driving home today, transmission stopped shifting. Stepped on the gas and nothing. Shifted up and down and barely made it home in 1st gear. Luckily was real close to house. So as it stands, car will shift in R fine, 1-2 barely moves, anything else the car won't move, just rev up. Before I take the car to a Transmission shop, is there anything I can check on my own? Maybe something simple? Fluid isn't too bad but could probably be changed soon. Or does it sound like this tranny might be shot. Engine light never came on. Any help or advice is greatly appreciated! Thank you!

BTW, this car has 160K.

Sounds like tranny is shot you could drop the pan and see if there are metal shavings in it

To me, it kinda sounds like you lost the forward band.

yep you need a new trans sounds like.

Forward band is shot. Experienced the same symptoms. Trans had to be rebuilt

Not sure if this helps, about 8 months ago I washed my engine bay good with degreaser and sprayed lightly with water. Hoped in my car when the motor was dry and same thing was happening to me, but mine would barely move forward, check the big wire harness on the transmission for shorted wires. Or mabye something got wet.

Everything worked fine after 24 hours when it was dry.