Weird Noise when accelerating uphill lightly

[Gtpamphile]

Started hearing this odd noise when I lightly accelerate up any incline/hill. It'll make the noise continually unless I Rev the engine past 2-3k rpm or more and it'll make the noise more lightly after the hill on level ground for about 20-30 seconds and then it stops completely (it's audible with the window's closed). Not sure what to describe the sound but it's sounds like a rattle noise to me. The noise also stops when i let off the throttle. It started a few days after I had service done at a Nissan dealership to replace the sport mode switch since it wasn't working. Not sure if it's something loose that wasn't tightened somewhere or if it's something more serious.I've been pretty meticulous with doing regular maintenance on time with what the service book my car came with says. I recorded a video of it and a audio recording but I wanted to ask on a forum if other's have ever experienced this.

[LuckySeven]

I had noises plus a whine anytime I put pressure on the gas either going up hill or 60kmh+.. turned out to be the transmission failing. Still under warranty ?

[Gtpamphile]

Yeah the car should still be under warranty since it's only 3 years old. I hope it isn't the transmission, seems a bit extreme. Acts normal under any other instance it's just during a hill it makes that noise for a brief period.

[Kapok]

Did you ever figure this out? I am having the same problem.