I had this problem on my last f150 as well right around 65-70k miles. There gear oil is leaking at the rear differential an drive shaft. I know it's a gasket that needs replacing which cost be a bundle last time. I was wondering if there's any kind of silicon sealer I could place around the gasket to stop the leak, I don't exactly have 1000 laying around with the holidays here.. Any input would help. Also how long can I go with this problem before it just blows up/breaks/ruins my truck

 

It sounds like the front seal is leaking and as long as you keep the fluid level full you shouls make it through Christmas without any issues. The seal isn't to hard to replace and you won't need any sealer if the job is done correctly.

 

Which fluid should I be checking? I just got an oil change an they're supposed to check all my
Fluids but who knows with them

 

Pinion seal leak WILL get on U-Joints (driveshaft). Seal can be replaced fairly easily by a guy who knows how to re-establish pinion bearing preload, after removint the BIG NUT!

Rear cover leakage is blown toward the rear of the vehicle, will not get on the driveshaft, even after vehicle is standing, as the pinion (entire center section) is tilted UPWARD in front, to establish drive-line angle.

imp

 

The leaks about a foot up onto the drift shaft, then it's leaking all onto the differential .. Not sure if its worth paying for a rental to bring it to a shop during the week or if I can get a few more weeks out of it an bring it just after the holidays (I'm not made of money)

 

Pinion it was, all scooped out and fixed for 145$ an that's on cape where everything's more expensive... Thank god

 

Bought the part a few months ago for 5 dollars from ford and paid a shop around the corner 65 dollars to put it in...took him 30 min......piece of cake...