Hello folks, I just want to share some info, about this job, a way to say thank you for the help I get here , is posting good info to help others. My Expy Eddie 2006 had developed a leak on the front differential seals, both sides as well as the pinion seal ( back ) . I have replaced the seal on the passenger's side last year, today was time to tacle the pinion seal. Below is the part number for the seal. It costs $18 at the dealer.
Raise the front of your truck, esnure support with jack stands. Let me just tell you, you will need an air wrench. It will make your job a lot easier. Also make sure you mark the flange and the shaft so you can put back when it was. Those 4 bolts on the flage will require a 12MM 12 point socket. Get one at Sears, or autoparts store. Preferably a 1/2 inch . The torque for those 4 bolts is 83 Lbs/ft. once you remove the bolts grab the shaft and push backwards to separete it from the flange. Make sure the shaft is supported. I used a piece of 4x2 on top of the cross member.
Picture above shows flange in place , note center pinion nut not yet removed.
The above picture shows the flange in place, note I have already removed the big nut on the center it takes a 27 MM socket. You will also need a gear puller to pull the flange out once you have removed the center nut.
Above close up of the flange removed. Below you will now see the seal exposed. It is kind of hard to remove it, be careful not scrape the inside of the differential, I used a small screw driver to remove it.
Here is a close up shot of the old seal in place.
Make sure you lubricate the housing with gear oil before pushing the new seal in . I used a small hammer and a piece of wood to push the new seal in. Be patient. Assemble is in the reverse order.