I just wanted to post my feedback on my own experience to help the next guy. This forum helped me confirm my own issue, and I wanna pay it forward...
2018 SL purchased used. 35k mi.
Exact same issues described in this thread.
100% of the time when AC was running (didnt matter if it was start of the day or truck was running for a bit) truck would sound like a jet engine until I hit about 35-40mph, then would finally quiet down. Fully audible in the cabine with windows up. Would happen on EVERY acceleration. When AC was NOT running, symptoms occurred maybe 10% of the time.
I hadn't driven a big truck since my 2004 F150 years ago, and I saw a LOT of "counter" posts in various forums also saying the behavior was "normal"...so I didn't think TOO much about it...
...that is until my 2 yr old daughter took her first drive in daddy's truck a few days after I got it.... and started crying saying she was basically scared to ride in "daddys loud truck"...and thats what drove me into action...
After reading some more up on it I did the "spin the fan" test while engine was cold - and compared to my 2012 Frontier it definitely felt like it was "seized" (at least to me it did - full disclosure I am NOT very mechanically inclined)...while my frontier spun maybe a 1/2 to 3/4 of a rotation, my titan barely moved a couple inches.
So I took it into the shop (thank you awesome warranty) and Nissan confirmed the symptoms I described. It took a few days because they were slammed and had to order the part, but they replaced the fan clutch assembly without any need to "fight for it" (guess maybe I am lucky in having a decent Nissan dealer close by?)...
Now the truck runs awesome, AC or not, no matter how I drive it. My daughter loves riding in "daddys new truck" (since she sits so much higher than the frontier was), and I couldn't be happier.
So, just wanted to drop this line in for the next guy, because while its normal for the fan to kick on during maybe warm up or some crazy heat (fyi - it fluctuated between 85-99 outside during this whole episode), it should definitely NOT run the way I described mine doing at the beginning of the post, and its worth looking into.
And as myself and a previous poster mentioned, the truck doesn't need excessive mileage in some cases...mine was at just about 36k, and his was like 6k.
If you're out of warranty, so you have an idea, the part they ordered was about $275 for me and they "billed" 1hr of labor...but there was no cost to me since it was still under warranty.
Hope this helps someone in the future...
