Automatic transmission. I bought the car at 55k miles 8 years ago and had the transmission fluid flushed within the next 5k miles. I haven't changed the fluid since then. It now has 140k miles on it, and 2 years ago, it stopped going in reverse. I drove like that for a couple/few months until I bought a second vehicle. Since then, it has been decorating my curb. Recently, I've come across some willing help and extra time; so, I'm hoping to get it running well again.

When I shift from park to reverse, I get a strong lurch, and then, it acts as if it is in neutral. If I then shift into neutral, it doesn't do much of anything. It used to go forward just fine, but now that it's been sitting for so long, that isn't so good anymore (but I think that is due to old gas and oil). I've tried disconnecting the linkage and manually turning the ****, but still no reverse.

One mechanic told me I should flush the transmission and replace the filter before anything else because it might just be 'sticking', but I'd like a second opinion.

I do plan on draining all the fluids and replacing prior to starting it back up. I just want to make sure that I'm not wasting my time by flushing the transmission if it is garbage.