I am changing out the oil in my rear diff. I see there is no drain plug, so I guess I just pull the cover off and have a large oil pan to catch the oil. I do have the limited slip additive to put in. Once the cover is off, will any ware be easily noticeable? I have a new gasket to put on the cover. When I go to fill, I just fill it until it starts to come out of the fill hole? I am assuming the only plug that is on the rearend is the fill plug, it is about half way up on the rearend.
Thanks in advance for any advice!

 

You pretty much nailed it on the head.

Guzzle's site has complete picture tutorials:

Welcome to guzzle's Rear Differential Maintenance Web Page

Welcome to guzzle's Front Differential Maintenance Web Page

The Dana 50 and 60 have the exact same procedure for changing oil.

 

Thanks housedad!
I am using royal purple synthetic 75w-140. It has the limited slip additive in it already, should I add more or am I ok??

 

Also, I got a gasket for the rear cover, should I use this or should I use RTV?? The guy at the parts store told me not to use RTV if you use a synthetic.???

 

I have been told to add additive. I have done it every time i did something to the rear.

 

If you add too much additive then you will lose the limited slip and it will become limited grip...

If it already has additive, don't add anymore (yet). If you hear/feel chatter in the rear when you turn you should add more. I would recommend 1oz at a time. Then drive around some more to see if the problem is solved or persists. I used Mobil 1 syn 75/140 in mine (which comes with the friction modifier in it) and have not had to add any at all. I did buy a 4oz bottle from Ford just in case but haven't had to open it yet. If I get any rear end chatter then I'll add.

I've never heard of a gasket for the differential cover. I used RTV with my synthetic and have had no problems with it at all.

 

Hmmm, Im beginning to wonder if I should use the gasket or use RTV. Im thinking maybe taking the gasket back and getting RTV. Anyone else have any thoughts on this??

 

I did mine about three weeks ago and everyone said to use RTV. I am surprised you could even FIND a gasket for it, both Ford dealers by me said there is not one made for the rear diff on the X. I'd go RTV, I used it and also used synthetic (Amsoil) and also have had no issues!

 

Odd, my parts store had one in stock! I did take it back and used RTV. Getting ready to fill it back up

 

At what point should the rear fluid be changed? My mechanic is ready to do it whenever I am ready.
But I only have 52,000 miles on my biggest baddest SUV on the road!

Wait a minute, it can't be the biggest and baddest; it ain't go no diesel. Second biggest baddest SUV on the road!

 

Don't open that bottle of modifier yet! See if it chatters on the turns first. You can turn it into limited grip as Brian said.

 

If its a rubber gasket I'd use the gasket, but if it's one of those fiber type gaskets then just RTV it!

 

I just used RTV. I didnt add any additive yet, im letting the truck sit for the night and will test drive it tomorrow and see if I need to add any additive.
Thanks for the help everyone.
Also, everything looked good inside the case.

 

You can remove the VSS and fill it from there with a full 4 qts.

 

You could but... I'm pretty sure the fill is where it is for a reason. You only want so much fluid in there as you need room for expansion and you don't need the entire diff. assy. sitting submerged in oil.