Front Pinion Seal Leak after replacement

[rc1626]

I just replaced my front pinion seal on my 99 Explorer 4WD as the old one was leaking. After replacement all looked good for about a day until it started leaking again. Replaced it a second time and it is still leaking. I don't think it is leaking when the truck sits but more so when the truck is moving and the gear oil is being sloshed around.

I was recently reading up on some threads on the board and some mentioned about setting bearing preload. I don't know if incorrect preload would cause a leak or not. It seems more like it would probably have more to do with premature bearing failure. So looking for feedback please. Any ideas on why I may be experiencing this reoccurring pinion seal leak? And how does one set bearing preload?

Any and all help appreciated.

Thanks.
Rob

 

[waskly]

does the yolk / flange have a worn in grove from the old pinion seal ring?

might need a new yolk/flange.

 

[GETMYBELTSON]

Make sure the vent tube is not clogged.

 

[rc1626]

Thank you for the replies. I will certainly check the yolk flange the next time it is apart. Where is the vent tube if I might ask?

Thank you again.
Rob

 

[storlied]

On the top of the diff in a spot you can't reach unless your magic.