New pinion seal leaking?

[cashmoney37]

I just changed gears on my mountaineer from 3.73 to 4.10. I put all new seals bearings. Everything went perfect no problems. Well its been two weeks since the install and today I noticed the pinion seal is leaking. Its seeping anough were there is a film runing down the diff. Why is that? It didnt leak with old seal. Everything was clean when installed. What would you recomend I.do

 

[RomeovilleIL]

If you want it fixed, the only option is to take it apart and inspect.

If leaking at the pinion itself:

Oil can work itself out the threads of the pinion nut if it wasn't sealed with thread locker or rtv (thin film of indian head gasket sealer on the last few threads gives good results)

There might have been a groove in the pinion. Usually looks like a shiny line, can be felt with fingernail. Use a speedi-sleeve or set seal at different depth so the groove isnt touching the seal. If severe, replace the pinion.

Seal might have been damaged during install. Retaining spring might have been pushed out of alignment. Might have a nick or cut.

If seeping at seal/differential body instead of the pinion, then either a damaged seal or sealing area. Best fix is pull seal, put thin coat of RTV on sealing area, then reinstall. Let dry before filling.