1994 Accord transmission? Engine issue?

I have a 1994 accord where whenever its in a gear, it feels like every so often while stopped (holding the brake) it makes a thumping feeling, sometimes repeating it 2 or 3 times and then nothing, then a short moment later (no real determination of when its going to happen next) and repeating 1-3 thumping feelings. It doesnt happen while the car is in park, and usually not in nuetral. The engine idles normally and Im not sure if its just something with the motor or what. Any thoughts would be welcomed. I think I cleaned the solenoids at one point, but dont think they have anything to do with this.

Here is a short video of the motor with the behavior