The last time the OP commented on ClubFrontier it was on this thread 4yrs ago. I don't know why I didn't think of this early, but I bet he didn't resurface his flywheel so it was burnt and/or warped and just burning up his new clutch when ever he put a load on it. A bad pressure plate from the factory could also do this and it's not unheard of.The issue with MY Frontier was NOT that it was a manual transmission, per se. It was the #$%^@ Clutch/Flywheel that was the problem on my particular model.
All that said, I reluctantly moved into an automatic transmission (first in 35 years) Titan and will NEVER look back. Not for towing, I won't.
I have just returned from a 1708 mile trip over and through a couple of mountain ranges and I dread the thought of having to be shifting that whole time.
AGAIN - the problem I had with MY Frontier was due to the POS dual plate flywheel on that model.