I recently replaced the rear differential cover and seal to stop a leak from the rear differential, now I am looking to do the front differential seal and cover (also leaking).

Does anyone know if it's as straightforward as the rear? Open cover, let drain, replace cover and seal, fill?

Also, does anyone know what the part numbers are for the front differential cover? The rear is the 9.75, the front looks more circular. Is the front the 8.8 like some rear covers? Are the 8.8 rear and the front the same piece?

Truck is obviously 4x4 if that matters...

Thanks!

 

Front and rear gearing should be the same.

 

I've done it....... no different really.

But..... there is a lot less room, 1 or 2 of the bolts are difficult to access, and, the cover kinda slips in/out with a specific orientation. Also, oil residual from changing oil filters gets all over the upper part of the diff and cover and it is generally a mess.

After you clean everything up and before you apply your new sealant/gasket material...... practice moving the cover into place a few times so that you are confident on how to best move it into position and clear obstacles so that you don't screw your gasket material up in the process when making the final cover placement.

Hope this helps!!!!!!

NOTE: There is a vent hose (breather hose) that comes off of the top of the front diff and extends upward and attaches on the side of the engine compartment on the drivers side. Make sure it is properly elevated and attached. I found mine detached and coiled up on top of the differential. So. basically the first time you encounter axle deep water you will get water in the diff .......... like me . I purchased my truck used with 20,000 miles and it was apparently like that when I bought it. I never noticed it until I changed the front diff fluid at 100,000 miles. My diff fluid looked like muddy water and there was a rust line about 2/3 up the diff cover from the water. Yes I spent a great deal of time cleaning it up and coated the inside of the diff cover with some anti-rust primer. The whole project was a PITA for me.

 

Awesome write-up, thanks for all the info! This is the insight I was looking for. It would also explain why the front and rear covers are different, since the front one is vented... any specific reason that the front is vented and not the rear?

EDIT: I think I found my answer... The rear is vented off the axle, not the cover directly, correct?

 

If you can get it up in the air on a lift or front ramps its not terrible but those top center and left bolts are a real PITA if its just on jack stands. Extensions and swivel joints are a must but the extensions can actually make it harder, you just have to get the right combo of joints and bars to get at it without clearance issues. I used gaskets and RTV on mine, I think I did, I know I did the rear like that but its been awhile, might have had to RTV the gasket in place because its so tight to line up, the dry run install advice above is smart, I don't think I did that lol, I know I made a mess. I hate cracking gaskets on my truck, only if it has to be done or I would pump it out/in, sucks.
I don't have the FX4 but no vent on my rear cover.