Brake pedal slow to rise when reversing

Every time we put the Xterra in reverse the brake pedal takes a long time to rise back up, releasing the brake. The pedal slowly moves up, making a noise as if the brakes are still on, then when it’s all the way up it reverses just fine. Moving forward the brakes work just fine! The transmission was recently replaced (but I had the same problem before the replacement). I took it to two different mechanics and they told me to take it to the dealership. However I don’t want to exorbitant prices at the dealership. Please help…