Disc Drive is not auto inserting discs

So I recently picked up a PS4 with a faulty disc drive to see if i could fix it, and the problem is I can't find what's causing the problem with the disc drive. Essentially, it will not pull in discs, or eject them. Using the manual eject screw, I can move the disc in or out, and if I put the disc in, then turn the PS4 on, it will read the disc just fine. The only problem seems to be the fact that it will not pull the disc in, and when I hit the eject button, it makes a beep, but won't make any sounds internally to indicate that it is attempting to eject the disc. I've taken it apart, and all the rollers and gears seem to be in the right place. It doesn't make any noises whenever I try to push it in to get it to auto insert, which I think means that it could be the sensor not noticing a disc, or maybe even the motor not being capable of pulling the disc in, however I don't think the latter is the answer, as I can't hear it even making an attempt to move things inside the PS4. I'd like to try to narrow down what part it might be before I try to buy and insert replacement pieces, just so I don't have to buy the incorrect piece since I don't know what's wrong. Any help would be greatly appreciated