i crawled under my 05 f150 and on the driver side rear it looks like the disk cover is soaked with oil or something. the passenger side is completly dry. what is this. i can smell something too like a burnt smell after stop and go driving when i get out. brakes are new too.

 

It could be one of 2 things. Either brake fluid (clear) or differential fluid (brown / black). If it is brake fluid, there is a leak somewhere (hose, caliper, fitting), and you likely dont have rear brakes (you would probably feel this). If it is differential fluid, then either the oil seal, or bearing (or both, since if you replace one, you should do both). If it is differential fluid, then ANY driving you do on it could be catastrophic-ruin gears, axle, axle housing. If it is brakes, it is still unsafe to drive it to the shop, but people have done worse by driving with only front brakes. Either way, you need to find out which it is, and fix it before driving any further.

 

Gear oil is loaded with Sulfur, so just take a whiff. It should be obvious. If your truck has an 8.8" axle, click my signature link & look in that photo album. It shows just about everything you'd want to know about fixing that.