I filled my rear differential today. Took a quart and a half before it started coming out the fill/drain hole. The hole is located at the rear of the diff. I know it was bone dry because the guy who rebuilt it told me to fill it. That same guy and the local Ford community are all in agreement that it should take five pints. Anyone have a guess why I'm two pints shy?

 

You should have a fill plug on the side of the pumpkin , is it higher than the one on the rear of the housing ?

 

No fill plug on the side. In better light I found one in the front " honeycomb" part of the diff, BUT, it measures at the same height as the one at the rear. ????????

 

Are you sure the rebuilder didn’t put "some" oil in, to prevent rust, etc.?

 

That was my thought. Difficult to know for sure. Don't know if the work was done in the morning or the afternoon.......if you know what I mean......He said he gave it to me bone dry. He even put a piece of tape on it reminding me to fill it. I'm going to try to find a different way to approach the subject. I have respect for his knowledge and skill. He has helped me a lot.

 

is it for a dragster and very narrow?

 

NO, but it does bring up a question. On initial fill and before start up is the 5 pints confined to the center housing or should some migrate into the axle tubes?

 

when you go around a corner it goes where it wants, thats fer sure.

 

A lot of oil clings to all the gears, too. I'd drive it a mile or two, let it settle, and top up. As said, going around corners will get it out in the tubes.

 

You might try jacking the rear up one side at a time for 15-20 minutes to make sure you have oil to the bearings ,then re checking the level .

 

I generally fill through the vent...often much easier and I put in how much I want.

 

I just filled a newly rebuilt 8 inch rear through the brake line vent brass "Y" in the top of one of the tubes. another way to fill/empty is to jack up on one side, and pull an axle out. a bit "shade tree", but it works. just don't mess up the seal.