Just had fuel pump replaced gurgling noise

I just had fuel pump replaced. It did not fix the problem of van not wanting to accelerate do another mechanic said bad gas and transmission fluid too low could be problem. I put in new gas and two quarts of transmission fluid. Took it for the separate test drives and it hesitates and starts to support if trying to accelerate uphill or if trying to go from forty to fifty mph. Also, problem I notice now buy not before is when I first turn van on, I am hearing a weird hum and gurgling coming from the back of the van.