I think I should change my diff oil front and rear, I've done it on my Quad but thats all just a drain and fill, Now I gat a(new to me, 100000km) 05 FX4, and I would like to find a link preferably with pics on how to do it and what to inspect when im in there. I have looked but came up with nothing. Im changing due to a humm/howl in the rear at all speeds.

 

take the cover off..maybe 12 bolts 13mm i believe...then get some black RTV sealant and put er back on and then after a few hours fill it back up and dont forget the limited slip additive!

 

are there gaskets that seal the cover? is anything going to fall out on me? what do i look for when its open Signs and symptoms of wear/damage?

 

nothing is gonna fall out except the old oil..and there is black RTV sealant that seals the cover..look for metal shavings (which it will have some) and chunks of metal..you can even lift the trucks wheels off the ground and rotate the tires and watch the gears spin to see if anything looks odd

 

make sure when you go to install the cover you have all the old sliicone cleaned off really well and no oil resedue on housing, other wise the rtv will not seal and the cover will leak

 

this is helpful. So this change should be done every 100k?

 

100,000 miles is what the manual states but if you actually use your truck as a truck you may want to at least do the rear diff before then.

 

Depending on your use, you may need it more often than that. A couple of quarts of fluid is cheap, compared to what a new differential will cost. Check your fluid regularly, and always before & after 4 wheeling. Before, to ensure that you are not going out there with fouled fluids. And after, to make sure that your fluid is still in good condition. I also make a habit of checking my dipstick at every engine oil change. It doesn't hurt to look. That 100,000 mile suggestion is fine if your truck is only used by grandma to get groceries. As they say, YMMV. Your mileage may vary.

 

Whenever I pick up a used car, I always like to change out all the fluids, belts, and hoses. Some may argue that it's not neccessary. But to me, it's preventative maintenance. Why wait for a hose to burst, belt to snap, or run it with old fluid when you don't have to?

 

dont fortget this is also gonna be expensive the gear oil you need to use is sysnthetic and is about 18 $ a quart and you need 5 of them,

 

Thanks for the helpful responses.