1991 190E 2.3 112k miles

I was crusing happily down the highway at 100 95 mph or so when I decided to take an off ramp.

There was a stop sign at the end of the off ramp, so I slowed down.

When I pressed on the gas to speed up away from the stop sign, the car wouldn't move. It wasn't engaging 1st gear.

There was no noise, no smell, it was a big surprise.

I pulled over and looked the situation over.
Reverse WORKS
Drive DOES NOT WORK
1st gear DOES NOT WORK
2nd gear DOES NOT WORK

When I pick Drive, 1st or 2nd with the select lever, I hear nothing. There is no little clunk like usual. Completely silent.
When I rev up, nothing happens. I even backed up on a hill and coasted down the hill hoping the car would skip 1st and jump in 2nd or something, lol. I've been reading about automatics and maybe within a few hours I'll understand them better.

Any ideas??? Right now the plan is just to get it replaced ($1600 at least), but I have the feeling it might be something minor. The car is stranded next to a highway right now, but I'm going out tomorrow to change the transmission fluid in hopes that might do something.