I have a 2014 2500 ctd 4x4 I bought brand new. I am at 40,000 miles. Somehow I have overlooked the service on the transfer case and the front and rear diff. So I looked in the book and it says to change the transfer case at 48 months or 60,000 miles. Oops I went way over on time. But I cant find where it recommends when to change the axle fluid both front and back. It only says if used for heavy towing or taxi service to change it once a year. But if not used for any of that, makes no recommendation of when to change. When do you all service your axles? And does anyone know what the recommend axle service is? Have I already screwed up on this. Truck sits more than it should in the shop and is only used to tow our camper about 6 times a year, and a 100 mile round trip to work when I think its sat too long. Sorry for long story..... Thanks all.....