As the title says, my 2002 Monte Carlo LS has been shifting hard to where it kicks the whole car and makes a “thud” sound. It’s got about 230,000 miles or so on it?

it also dies randomly while I’m driving slower speeds or idling, such as when I’m in town or driving in a parking lot. This locks the wheel and frightens me. I can start it back up just fine.

third problem is due to me not driving it for a full year due to those safety concerns I have: the car is dead. I assume I need a new battery at this point; I’ve tried jumping it but no luck.

this car means a lot to me and it sucks seeing it fall apart like this.

 

More than likely your transmission Is failing. If you use a scan tool you will see code P1811. Max shift adapt. The computer has added its maximum adaptive pressure and still cannot get the shift times to where it wants, so it sets this code and commands full line pressure. Some people have had luck with installing the Transgo shift kit for the 4T65E transmissions. You have to drop the pan to do this. However with the mileage on the transmission this is only buying you a short time. It will need a rebuild more than likely. Be glad it lasted you that long.

As for the stalling thing, it could be a restricted fuel filter or failing fuel pump. It also could be other items like crank position sensor, usually they will fail when warmed up. But best to look a the data from the engine with a scan tool rather than do a shotgun approach with parts tossed at it.

 

Years ago I was a Sales Rep and I traveled alot with my car. The shop I went to always treated me well and they would have me change the Trans fluid every 50k so it looked Red and not Brown. I put over 400K on an Olds 98 and never had an issue with the Trans. I didn't abuse it either and when I took off from a light (I didn't floor it like I see people do today). If you take care of it they last along time.

Check your Vac lines for the Random shut off thing. If you have a leaker that will cause that issue.