How to fill 1996 Crown Vic differential through vent tube

I have a 1996 Corwn Vic with east coast rust...

The differential fill plug looks hopeless and the shops I have taken it to won't touch it.

I\\'ve asked if they could use the vent tube to refill the oil after draining, but have been told the hole was too small.

I haven\\'t been able to find a picture on the internet showing the differential cover and exactly where the vent is and what it looks like... can anyone provide a link?

I\\'ve read that there should be a candy cane shaped tube attached to the vent, but I\\'m not sure there is (could the vent tube have rusted resulting in the tube falling off?)

Would appreciate hearing from someone who has actually filled the differential using the vent tube: can you just place the tip of the gear oil into the vent tube and pour the oil in? Or do you for example have to connect a 1/4\\" tube to the vent tube and to the tip of the gear oil container and raise the gear oil above the vent tube to do an \\"IV drip\\"? Is there enough room under the car to do that?

Would appreciate any help from you experts out there -- thanks.

With Regards-
Sam

Liberal amounts of rust cutter allowed to soak for several days should do it. I mean for you to get underneath and spray it liberally every day for about a week should loosen it up. Try hitting the plug a couple of times with a hammer BEFORE attempting to unscrewing it. If I remember correctly, it's a 3/8 inch square hole, and I used a 24 inch breaker bar to get mine loose. Or find someone with an air gun to loosen it. You might have to find somebody totally independent from any shop. If it doesn't want to loosen, give up. That road salt will almost fuse the metals together worst than a bad waste line in a sewer. Try a junk yard to get a replacement.

Trying to use the vent hole is pointless. You won't have enough room with a hose installed to be able to vent the air OUT.

Thanks. Re: replacement, you mean the rear end?