The first one is missing the pawl for the reverse unit so that is out. The second probably has a broken wire or bad reverse drum. The metal arm seen in the cab of the second is the pawl. This should move when power is applied and then cut, like an e unit. If it does not, the reverse is not getting power.
AF is hard to work on if you are not well experienced and difficult to get parts for. If you are not comfortable doing it yourself i would let someone do it. Those reverse units can be tricky.