Diffs Leaking

[str8wkd]

both my front and rear pinion seals are leaking, I have never done this on a ford superduty diff can I just take the pinion nut off and pull seal and replace or is there a crush washer in it that has to have the back lash reset when done.

also what weights of fluid think I read 90/140 R and 89/90 F, if I use Synthetic in rear with additive is that enough add or do I need more

[2 stroker]

Originally Posted by str8wkd

both my front and rear pinion seals are leaking, I have never done this on a ford superduty diff can I just take the pinion nut off and pull seal and replace or is there a crush washer in it that has to have the back lash reset when done.

also what weights of fluid think I read 90/140 R and 89/90 F, if I use Synthetic in rear with additive is that enough add or do I need more

When i did mine on my 97 i marked the nut had the front end up about a foot dropped the driveline removed the nut replaced the seal replaced the nut turned to the same mark lost no oil replaced the driveline. 5k pulling a 5er all good.
If you drop the oil most come with the friction modifiers but if you need to add only 2oz at a time check by making a hard turn at walmart parking lot if it jumps add.
2 stroker

[str8wkd]

Thanks I guess after get done my heater core they will next.

[scha0786]

is there a how to somewhere on this? my front is sketchy too. I'll need to replace it this summer but good for the winter I think.

Also what kind of fluid can I use, I want the full synthetic.

[2 stroker]

This is what i used Amsoil
Front-----Severe Gear 75W-90
Rear------Severe Gear 75W-140
2 stroker

[jd4010]

Originally Posted by 2 stroker

This is what i used Amsoil
Front-----Severe Gear 75W-90
Rear------Severe Gear 75W-140
2 stroker

I 2nd the Amsoil. And no, I'm not a dealer! The oil is good stuff...works well.

[str8wkd]

Might be finally doing this 2mar anyone know how many bottles for each diff.