My 98 f-150 is leaking rear diff. oil from both input and right output axle seals, replaced input last year this time and now needs replaced again, seems like a pressure build up, I think the breather is not working properly, i have blown it out and axle seal leak stopped for sometime. should this breather be replaced and how hard is it to replace?

 

Hi John;Do you work for CSXT???? First thing to check is your clutch pack.make sure all is ok there.once you get dirt in the oil it dosnt take long to eat the seals. try to flush the entire rear end. If you have been in water that will also destroy your seals.When all is finished put in Redline oil....Not Ford oil. also John, check the race for a nick or gaulding. You also didnt say how many miles is on the truck..well anyway good luck OLDGRAY

 

I have spent some time looking into the problem with my axle seals and found that after taking it to a Ford dealership to have my fluids changed. the Tech had overfilled my rear axle. I had checked the fluid levels once I had them done (due to experience with someone who forgot to fill with oil in another truck of mine.) But to make a long story short oil level even with the fill plug. Drained rear axle and inspected and refilled to 3/8 below plug and no leaks to date.