My rear differential is leaking around the yoke where the drive shaft enters. I have no idea what this is called or if it is a seal or bearing. It just started today while offroading. Any ideas of what I am in for? Do-it-yourself or cash wise?

 

Mine leaks too, My rear pininon seal is bad, caused from wrong angle on my driveshaft.
Bought my seal from ford, less than 10.00. Also you might want to chk to make sure that your pinion nut hasnt backed off.

 

Thanks so much! I will check that out. I have a 6 inch Donahoe Lift that I put on it a couple of months ago. I used the carrier bearing shim kit with enough shims for 6 inches of lift. Turns out they sent the wrong rear blocks and I only have five in the back. Would 1 inch cause enough incorrect angle to cause it to leak?

 

Well i'll tell you, My truck has had the lift on it since it was new its a 2000. I bought it from a friend, and he never put the carrier bearing spacer on it, cuz at the time no one new what was causing the driveline shake, When i bought the truck in 03 i did some research on driveline angles, and found this site, and since then i have installed a 1inch carrier bearing spacer that i made. I have no more driveline shake. But with about 90K with out a spacer, im sure thats what has cause the pinion to eat up the pinion seal. I havent changed mine yet, not leaking bad enough yet.. so im putting it off.
Im going to change the rear diff oil when i change the seal, If you plan to do this , make sure you get the right weight oil for your rear end, ford uses 2 weight oils, the wt of the oil is stamped on the ID tage onyour rear diff cover. And make sure you get the posi lube also.
I have a Fabtech lift on my truck.

Bad thing about these trucks is that the driveline has a shudder at stock height.

 

Thanks for the tips. I agree with the stock shudder. Mine has actually improved with the lift. Go figure?

 

You will want to check your vent line. Check the like and the metal nipple that the line attaches to. Mine was plugged when the seal started to leak. I guess it was building too much pressure.

 

Will do. Thanks for the info!