Q: 2001 Chevy Silverado changed transmission fluid and filter now it will shift but won't move even in neutral

Hey Jack. Thanks for contacting us today. It’s quite possible that the root issue is something very simple, like a shift solenoid not correctly attached or installed. It’s also possible if the fluid was flushed, that a few inner seals may have been damaged. This can and tends to occur on transmissions older than 10 years. I would double check any electrical connections to the transmission first to see if this resolves your problems. If not, contact a professional mechanic to complete a hard to shift inspection at your location.