I have a 2006 f-150, 4x4, and noticed what appears to be grease coming from where the drive shaft meets the rear-end. Could anyone tell me what this may be and if it's easy to repair? Thank you......from a broke college kid

 

is it a lot or just a little could be gear oil if you can crawl under the truck and give it a good looking over you shoul be able to tell where its coming from and see if its grease or gear oil.

 

It's likely the pinion seal. As long as you don't see any drips or marks on the ground after it sits for awhile you should be ok for now. Pull the fill plug on the side of the diff and stick your pinky in. You should feel oil near the bottom of the hole, if you have to really reach in to feel it then there could be a slow leak past the pinion seal. If the diff seems full then no need to panic for now. Just keep an eye out for any signs it may be getting worse.