Transmission won't engage

[Cooper33]

I have just inherited a 67 SWB stepside with 283 with 2 speed auto trans with 49k original miles. It was my grandfathers. It has sat for 2 years, but ran fine before that. Oil levels are fine and clean.

Problem, it wouldn't engage into any gear; R,D or 1. I did find that if I accelerate it would finally catch and begin to move. Bad torque converter? Or possibly just needs to be driven to warm up trans oil?

I need to do brake job before I will attempt to drive further than my driveway.

Thanks.