I had to replace my shift cable, followed the steps to a tee now it won't shift gears and I did adjust the cable. Someone said to check the gear box oil where is that located?
First, check the transmission's shift arm. It is what the cable connects to on the transmission's end. If it is broken, the cable is not at fault. The easiest way to tell is to have someone shift while you look at what is going on. Keep a vigilant eye on what is moving and what is not, as they should both move triggering action inside the transmission. If the cable and all other outer components are working properly, the issue lies inside of the transmission.
Secondly, the "gearbox" is typically a term used for the power steering gears and their housing. That would have nothing to do with your current issue. Whomever said that may have also been referring to the transmission itself, which is technically also a "gear box", and checking the transmission's fluid is a good idea. Without fluid, there is no pressure to change gears or function. This would indicate a bigger issue with the transmission itself, and possibly a leak.
Thank you for writing in.