Hey guys I just changed the gasket on my rear differential because it had developed a leak, but I cant seem to find the fill plug?? I have changed rear diff gaskets on Explorers, and F-150's and usually theres a fill plug on the cover of the differential thats used to fill it with clean fluid. Am I doing something wrong with the 9.75? I had a hard time even finding the gasket because for some reason every auto parts store I went to (and online) only listed Expeditions using 10 bolt, 8.8 differentials, so I had to have them look up a gasket for a F-250, so they could locate the 12 bolt 9.75 gasket. Could anybody tell me where the filler plug is or how to replace the fluid in the rear differential? By the way I have a 97 5.4L, 4x4. Thanks in advance.

 

the fill plug is on the front of the rearend about half way up next to the pinion shaft I believe on the right side if your under the truck looking rearward. just make sure the truck is on level ground and fill it up till it starts to run out the fill hole and close her up. also if the rear end is a limited slip make sure you add the friction additive before you fill it.

 

Just like t lindermann said.
~Gage~

 

Do you have a part number for that gasket? Or what year/engine you chose for the F250 to find the correct one.

 

Actually after a little homework I found out that the 9.75 rear diffs dont even use gaskets only RTV sealant. When learning this from Ford, I returned the gasket I got for the F-250, but I think I used a 97 F-250 4x4, 5.8L to locate the part.

 

Yeah that is why I asked, I know rtv is the normal replacement but thought a gasket would substitute quite nicely.

 

I made a gasket for my 97 with some gasket material I purchased at the Auto Parts store.