Transmission leak

My vehicle's damaged radiator was recently replaced after it skidded off the road. Few days later I discovered oil on the floor of my garage. There was a leak from a loose fitting on the transmission.

I filled the auto trans axle with 6 liters of transmission fluid. It drove only 60 miles afterwards.

Now the vehicle does not move on any of the forward gears at all and even on manual shift mode, but it moves normal on reverse gear. My question is, what are the possible components that could be damaged and why does the reverse gear work and the forward does not?