sorry if this has been discussed.....

i had mobil 1 75w90 put in not long after i got the truck, and i just read where there is a tsb that says nissan will replace the diff fluid with "nissan synthetic 75w140". i'm wondering if i should have this done to be in compliance with the tsb (warranty purposes down the road?). Are you guys that used the 75w90 going to switch over? thanks.

They will only due it if you have warranty work done, or you pay for a diff lube change out. It would be a lot cheaper if you did it yourself. If your not towing you should be fine with what you have until the change interval is reached. If your rear diff goes out you will still be covered with the 75-90W.