Help! rear differential cover fused on

[blue_goose]

So I am in the process of replacing the rear diff bearings and I can't even get into the diff! I took out the 2 bolts holding the cover to the frame along with 8 other 1/2" bolts holding the cover to the diff and no matter what we do it will not budge. I stopped after I broke off one of the tabs (not sure if that is the correct term) when hammering a chisel between the tab on the diff housing and the other one in the cover. I have fluid very slowly seeping out of the seal. I am at a loss of things to do-I have never seen this happen before. it is not hitting the frame in the back when i try to get it off, hitting it with a copper hammer dosn't do anything and I'm not about to hit it harder, trying to wedge a hammer a shim-type thing between the cover and dif isn't happening..... Any ideas?

 

[IZwack]

heat one corner with a torch (careful, plenty of aluminum parts around) and try the chisel approach where you just heated.

 

[crash594]

I think you have to remove the drive shaft then removed the nut at the drive shaft yoke and remove the axels. Then the whole shaft gears and bearings come out with the rear cover. Its not like the old Ford rears. I could be wrong but I am 90% sure I seen this in my 2001 Expedition and 2005 Explorer OEM manuals. I think this change was done around 2000. Thats why the 90 X's did not have rearend issues.

 

[IZwack]

I think you have to remove the drive shaft then removed the nut at the drive shaft yoke and remove the axels. Then the whole shaft gears and bearings come out with the rear cover. Its not like the old Ford rears. I could be wrong but I am 90% sure I seen this in my 2001 Expedition and 2005 Explorer OEM manuals. I think this change was done around 2000. Thats why the 90 X's did not have rearend issues.

That's not true -- the axle's cover does not support any of the differential's parts:

 

[crash594]

Sorry my bad. I went and got my 2005 book. 1st thig it says is to remove rear axel assy then remove the rear cover. Where I thought they removed the front nut is only to record the torque necessary to maintain rotation. for later. But there are 3 bolts holding in the housing 2 to the frame facing forward and one front lower insulator bolt.

 

[BajaXplorer]

great reason here NOTto use the gasket maker crap on a rear diff. Use the Fel~Pro 8.8 rear cork or rubber gaskets ($3-5 at any auto parts store) and you shouldnt ever have this issue again(if you decide to tackle the rear cover again)

 

[Four0Sport]

yeah i put shellac on my cover gasket last time i had it off.. its gonna be fun fun trying to get it off next time.

 

[IZwack]

I use RTV all the time and I've had no problems with it -- but then again, all the diff covers in my possession are steel so I can hammer on em w/o fracturing.

 

[blue_goose]

I didn't see the other 2 bolts that were hiding. looks like this problem is too big for us to tackle anyway as it requires more work and special tools then we can do right now or ever probally. So once I get the pan off all the way I'm going to seal it back up, maybe replace the seal that is leaking by the driveshaft if I can and add fluid. I guess I will just keep driving it until I can find a locker or maybe a limited slip and just swap diffs since the oppen has all the traction of a bicycle. Thanks for the help though, would have never have known about those 2 other bolts in the middle outside of the diff if I hadn't seen the pic.
BTW- I learned all this from the dealer today and he said one other thing- that the 02's hasd so many problems that Ford made it protocol to add fluid to the fill line then remove the speed sensor on top of the diff and add ANOTHER quart!! I guess this helped with the issue.

 

[IZwack]

BTW- I learned all this from the dealer today and he said one other thing- that the 02's hasd so many problems that Ford made it protocol to add fluid to the fill line then remove the speed sensor on top of the diff and add ANOTHER quart!! I guess this helped with the issue.

The problem isnt that the differential is low on fluid -- I think the problem is either in the design or the inconsistency between design and the manufacturing/casting process. The solid axle Ford 8.8 differential was a lot more reliable than the IRS so the problem can't be because of low fluid. Putting more fluid in there just means that you'll be extending the time between fill-up periods. Thumbs down to big Blue for this bandaid "solution".