Have Transmission Questions? Ask a Mechanic for Answers ASAP
No forward gears or motion at all, is that right?
The first thing is to check fluid level and condition. Your car may or may not have a transmission dipstick, depending on whether you have a 4cyl or 6cyl car (different transmissions). If you have a dipstick, start the engine and pull this dipstick out. Fluid should be full to the mark on the stick, and it should be red and transparent. If it's black and/or smells or looks burned, that's bad.
There is no electrical component or any other thing outside the transmission itself that can prevent forward movement. If you put the transmission in Drive, it should move, even if the electrical system fails. If you have reverse but no forward, you almost certainly have a transmission that has failed internally, and requires overhaul. Fluid condition check can verify this, or not. Burned fluid is dead giveaway, that means your clutches have burned away. Even if the fluid condition is good, the transmission probably still has a broken component inside. The only variable you can affect is fluid level, I would check to make sure it's full and has no leaks, but aside from that, you're going to need a transmission mechanic.