So I have a 1998 chevy silverado 1500 2wd pickup. I installed a used transmission in the pickup using the torque converter that came with it. After install the truck was driving fine shifting smoothly. The day it broke I drove it to work (30mile drive), then drove it to the store on my lunch, when I pulled into my work parking lot I hit the gas kinda hard then nothing. It won't engage or move in any gear I put it in. Also when I check the fluid level running and not running it's at the same spot. I dropped the pan the next day fluid still looks good and there is no metal in the pan. So I'm thinking that the fluid pump and torque converter are the issue now. My question is if I go ahead and replace both put a new filter and fluid in it what are the chances the transmission will start working properly again?

 

My next step would be to check connections. Since you where just in their putting in the new trans maybe something did not get plugged in all the way, and has gotten loose or fallen out. I would check all connections before blaming sudden transmission failure on an internal component.