Having transmission issues with my 91 Accord EX, 2dr, Automatic 93K.

Problem.
The car only has two gears. What appears to be first (probably actually second,) and what I believe to be third. Starting in D4 the trans slips and starts very slow. No auto downshifting. Manual shift to 1 a little slow off the line, not normal, shift to 2, no gear change, shift to D3, gear changes, shift to D4, no gear change. 3500rpms for 70ish miles per hour. Reverse works fine. I believe the fluid is at the correct level.

Supporting information.
I just replaced the motor on this vehicle. The previous motor had a four X six inch hole on the front side of the block. Many items on the passenger side of the car in the motor area were fried to a golden brown during the creation of this hole. One of the fried items was one plug from a two plug set for two different “sensors” located close together on the front side of the transmission. Trans fluid runs through these things. I wired new, (un-burnt,) plugs onto the old “sensors” using posi-lock wire nuts.
I believe my fluid level to be correct in that it shows the correct level on the stick. However, I removed the trans and the trans cooler lines, as well as doing both cv joints, lost alot of fluid. I have put in 2.5 quarts, which are the specs in my Haynes or Clymer, but I still have the shifting problem.

My questions.
What are those things on the front of the trans called and what do they do?
Do they go bad?
What is the capacity for a total drain and fill for the Auto Trans?

Thanks for the help
Rozarkie