I plan on installing my new Riddler covers and wanted to know If I am supposed to go with the factory fill amounts or if I should fill to the plug in the Riddler cover?

 

factory...

 

Yup! Factory. If you fill to the plug you will blow out all the overfill up your breather tube. Very messy. I have not done this myself but I have seen it.

 

Thanks, hope to get this done today!!!!!

 

With aftermarket covers, filling exactly to factory specs may or may not be quite enough. Here's a rule somebody taught me a while back. Works every time.

With the truck on level ground, fill until the oil is level with the bottom of the inside of the axle. You can take a zip tie and bend it 90 degrees to use as a dip stick. Stick the zip tie into the fill hole up to the bend in the tie. Take it out and compare the oil level to where the axle lines up with the diff cover.

I modified the procedure just a little. I put in the factory recommended amount and check. If a bit low, I add only enough to make the dip-stick method work.




Something to keep in mind - if you put in an lift your rear pinion angle may change (depending on lift). You probably won't be able to fit the recommended factory amount in, especially with stock covers, unless you get creative - like jacking the right rear tire up a bunch or parking on a down-slope. You can use the method above to visually see how low the oil will be by comparing the plug hole to the axle.

That's why most after-market covers have a high fill hole.

 

X5 according to everybody else, mine has over flowed by others over filling.

 

The red line in the picture above is about right. Here is a stock picture for comparison.
Whatever cover or angle you have, the oil level needs to be slightly above the level of the bottom of the axle tubes to permit oil to reach the outer axle bearings.

 

Thanks all I just did not want to mess anything up!!!