I had the same problem....it's the strut bearings...
Good points on the struts. Not sure about having to be warm, but worth a check.
Hey, in case it's helpful, I can tell you that I think this noise is from the strut bearings. Mine went out at about 58,000 miles. I had the Nissan service contract (7/70 duration), so they replaced the bearings and the entire strut assemblies as the fix. It would have cost me about $1500 for this fix (according to the dealer). The bearings are inexpensive (about $50 each as a replacement part). It's the stuts themselves and the labor that costs so much. I don't know if replacing just the bearings is an option (the dealer said the struts had to be replaced too).
The noise was louder whenever the car was warmer (meaning the bearings got warmer from the engine heat). I first heard it at about ambient temp of 75 degrees and it was intermittent. I got really loud at about 100 degrees. That's when it was clear (even to the hesitant dealer) that something was very wrong.
One consequence of the strut bearing repair were that the amount of steering effort has about doubled. I had the power steering fluid flushed (my expense) but that did no good. Finally, I bullied the dealer into doing the test described in the official Service Manual to measure the amount of torque needed to turn the steering wheel when stopped. Mine measured just below the maximum allowed (meaning Nissan said the effort was "normal"). But, as I said, the steering effort has about doubled, particularly in warmer weather (it's a bit lighter now that it's Oct.).
My car has about 72K miles now so my 7/70 contract has expired. Naturally, at the first oil change after the Service Contract expired (70,600 miles) the dealer "suggested" a $1500 repair to fix "slightly weeping Transfer Case seals." When I complained that Nissan should pay for that kind of repair I was told that Nissan would not do so. I recognize this as a dealer-packs-the-service-ticket scam, which in itself is annoying. But, if the seals really are failing, it says more about the car than the dealer.
I've written elsewhere on this forum about the Service Contract (I always buy them). This time, the $1495 I paid when I bought the car new in January 2012 has saved me about $5000. I've been surprised at the number of defective systems that popped up after 55K miles (strut bearings, driver's power seat base, A/C compressor, fuel pump, hood and hatch struts). Now the "slightly weeping seals." Geesh. What next?
I've been a loyal buyer of Nissan for a decade (my family and friends have bought 11 cars from the same dealer and salesman in that time). But, due to the amount of troubles I've had with my 2012 Murano, and the fact that Nissan has elected not to significantly facelift the 3rd-gen Murano (to date at least they done nothing but add CarPlay and the electronics that are now standard on most cars--no new engine, no styling changes), I'm actually thinking of buying a new-gen Toyota RAV4 early next year.
I know that Nissan is about a year behind Toyota in replacing both its Rogue and Murano (vs. the RAV4 and Highlander), so I suppose I could wait for new versions of both, but with the reliability of my 2012 now in question at a relatively early 72K miles, I may not be able to wait for any new products from Nissan. I'm not going to invest thousands of dollars in a almost 7-year old car, even if I've mostly loved it for all these years.
I hope this post is helpful to you (or someone). Perhaps you've already discovered what the fix was. If not, good luck.
Peace.
