Wyatt Smith
AH legend
The differentials probably have synthetic oil in them which will last a long time. I would change them at whatever the owners manual says or every fifty or hundred thousand miles. And of course after any submersion that may happen.I'd be interested in knowing from this elite group of truck owners, their thoughts on a few maintenance issues. It seems whenever I take my truck into the dealer for something, they print out a long list of recommended maintenance items. I come from a generation of changing out spark plugs every year or so (due to leaded gas) and remember when mufflers only lasted 3-5 years. Stuff lasts a lot longer now!
The question I have has to do with front and rear differential lube, transfer case and transmission. Regularly changing motor oil is a given. I am a believer in changing out the transmission fluid, at least once in the life of owning a truck. The other lubes, I'm not so sure. I've looked at YouTube videos on the subject and learned a few things. Most rear differentials don't have a drain plug. Rear differentials have a magnet inside the bottom of the housing. The magnet serves to collect and hold metal particles and theoretically keep the lube clean. Videos show pulling the cover off a rear differential and a muddy, grease like goo is on the magnet. The front differential and transfer case do have a drain bolt (on GMC). The drain bolt is magnetic and the metallic goo can simply be wiped off. If I were towing or hauling heavy loads, I could see doing differentials and transfer case more frequently (30k to 50k miles). Since I use my truck just to run around in and occasionally haul stuff, I am thinking if I service these items once, I am probably good for quite awhile.
Thoughts and comments are appreciated.
My 95 ford owners manual says to not even change the differential oil unless it has been submerged. But mine gets changed every year.
I bet at least half of all differentials got to their grave with the original oil.