When do you guys recommend getting tranny service done? My truck has 38k bought it with 36k. Also what about differential servicing?

 

(every) 30k is recommended, i have 50k on mine, and im about to do it. Hadnt touched the rear end, and dont really plan to until i go aftermarket gears

 

Change your rear end fluid!!! Go get some good high quality gear lube with similiar factory specs. I just drained mine and swapped in the Mag Hytech... got an extra couple qts (can hold over 4qts now!!) and the dif runs almost 50 degrees COOLER. the crap they put in it looked like black water!! I have 46,800 miles. I highly recommend Swepco gear lube... I am sure there are others out there that are WAY better than factory. Also note, it really depends on how you drive, my truck does some towing and off-roading.
And flush and filter every 30k on tranny.

 

The factory rear lube is full synthetic 75W140. No reason for it to get nasty, it should be good for 100k.

 

Technically nothing is full synthetic... all "synthetic" oils are derived from a dino base stock...
That said... since they use "full synthetic" you think they are going out, testing all the gear lubes then buying the best most expensive? Or do you think they are trying to turn a profit? I would never leave my gear lube for 100k... I don't care what the book says. Burning out, towing, recovery work, etc all take a huge toll on your rear end. If your ring and pinion fail... you aint going anywhere. More maintenance = more life.

Mercedes now are coming out with high interval oils changes. the tranny isn't suppose to be serviced til 100k... you know how many we have replaced cuz the oil became water and the owner thought they could go forever... This is just my opinion. To each there own