I have a 2011 Altima 2.5 SL with about 85,000 miles. I noticed recently I have a rattle or knocking sound on light Acceleration especially on an incline. If I accelerate hard I don’t get the noise. I don’t know if it is something in the transmission or the engine is tapping. It seams the CVT is always trying to get the RPM’s low so fast that it sounds like the engine is pining from the load the CVT is creating. If you rev the vehicle in neutral or park it doesn’t make the noise, it only happens when the vehicle is in motion. My Altima has new plugs and the oil is at proper level and always changes on time. I have also changed the CVT fluid twice since I’ve owned the vehicle. I have a new direct fit downstream CAT and flex pipe also. It doesn’t have any heat shields on it like the OEM one had that could be rattling. The sound is getting worse. It requires just the right driving condition to hear it. Light throttle from a complete stop, the CVT starts to variate into a higher ratio for economy and makes the engine struggle because of the load. If you drive it in manual and hold the shifts out it doesn’t make the noise. Had Nissan do TCM software update and didn’t help. Any suggestions would be greatly appreciated.