Nothing needed in the front... Only needed in the rear if you have the trac-loc option. Be careful when talking to dealers - most have no clue what they are talking about. They do like to sell stuff...

 

Just dont fill them to the holes in they are after market covers. Also I bought a pump that fits on the gear oil bottle with a hose, it makes filling them SO much easier. I got it at pepboys.

If you overfill them with an aftermarket cover on it will find its way out, my bonehead shop did it to mine and it killed an axle seal and pinion seal. It will also come out the breather tube.