Serpentine belt and idler pulley replacement

I just had the serpentine belt and idler pulley replaced on my 2000 altima.....when the mechanic did it, i was watching...and he put a jack under the engine to lift it in the bay so he could change the pulley....does that sound normal???he was doing it while the car was in his driveway....,
its making me nervous, there's a thump noise now every once in a while on the 1-2 shift on the auto tranny...related!?

what he did sounds normal, he jacked it up to release tension, and the thump would have nothing to do with idler pulley or serp belt. could be many things. try to have your transmission flushed

what he did sounds normal, he jacked it up to release tension, and the thump would have nothing to do with idler pulley or serp belt. could be many things. try to have your transmission flushed


that was done 2 weeks prior to the belt work. pretty sure its the mount, still happening, no other troubles.