hey all trying to get my 01 ready for a big ride across country-back to picturesque fort benning GA anyway, wondering how important it is to change the front and rear diff fluid ? i don't mean to sound dumb, but this has to do with the 4wd, right? or does it affect regular everyday driving too? thanks all---

It's needed for everyday driving, service intervals depends on vehicles mileage ?
At the very least ck them if low top off

thank you--i did both at 105k, and it now has 123k on it. but i did them in april 2012. so two years ago. is time or mileage more important?

the owners manual doesn't have any service interval that I know of. I think most OCD people on here just decide a number and stick to it, whether that's 25k, 30k, etc.

18k miles is not too much, you should be fine IMO.

Do you know if the change at 105k was synthetic or conventional? Synthetic supposedly has 50k+ type of intervals for gear oil.

For example, Amsoil is stating 50k on their synthetic gear oil if you aren't really towing or off-roading:

http://www.amsoil.worldclasslubrican...-oil-last.html

Also, just for your knowledge -- if you feel like you 'must' change one, do the rear over the front. First off, it's easier to change (I had to use a pump for front, but not for rear) -- second off, the truck is rear wheel drive when in 2wd (Which will be all your driving unless you are off-roading or something) -- so the front diff barely gets used, while the rear is constantly getting hammered.

since i fall into the OCD category, and i am trying to keep this thing til we retire from the Army (6.5 years to go-but who's counting?) i will probably do both now thanks for the advice- really appreciate it!

It sounds like you aren't out wheeling every weekend and this is just your DD. 18K miles you are fine.... I wouldn't stress over it or waste my time and money doing it.

But if you have OCD then you are going to do it anyway aren't you ;)

then don't forget the center diff, then lube the driveline (3 pumps max on the slider) and the tranny - drain/fill it - that works much harder than Any of the diffs and deserves special attention. Has the factory tranny cooler been bypassed?

Lower ball joints check out good for a long trip?

More details on above and lots of other info here: 3rd Gen FAQ, Tutorials, & Documentation Reference v2

Luck on trip! I'm headed west in 2 weeks for an approximate 4000 roadtrip. OCD'rs unite! Woohoo!

lots of great info thank you all. and yes, i will probably try to do it all....the joys of being OCD-sort of haha. good luck on your trip out west-