Is it hard to replace a transmission shift solenoid?

SOURCE: car shifts

Hi I am Vortash sounds like Torque slip check your fluid levels in the transmission. Rpm will rise if there is weak drive then as the vehicle reaches change speed it will snatch because the rpm is high .. if your levels are ok you may need to get your Torque converter checked out .. hope this helps regards Vortash

SOURCE: gears slipping

Either try changing your timming chain or it could be crank censor.

SOURCE: I have a 2002 pontiac grand am gt that is'nt shifting gears right

My daughter has a 2003 with the same problem. She took it to a highly regarded transmission shop. They told her it is not the transmisison but an engine performance problem. She took it for an oil change to check the filters etc and the fuel filter is bad. I will follow up if that fixes the problem.

SOURCE: the transmission gears are slipping.

the cheaper way is to call a junkyard and get another used transmission, with much lower miles. problem is that it is so old few yards will have an interchange on it. yes after 25 years a transmission can and will fail, it has been doing well for at least 15 years and deserves some praise. must have already been rebuilt at least once.

SOURCE: 99 Grand Am. No reverse

Hello and welcome to FixYa!
Looks like a faulty torque converter to me. If the torque converter is faulty, it shifts hard or may stay on a certain gear. Reverse can be affected too. I strongly suggest that you have a torque converter replacement if that's the case.
Before going to torque converter replacement, please do check the transmission fluid. If it looks or has a burnt smell then it can be the issue too. Burnt fluid may cause irregularities on transmissions operation. If that's the case then go for the fluid replacement first and if it still fails then it's time to have a new torque converter.
Hope this helps and thank you for using FixYa! Have a good one!