Thread: Ford 9"

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Ok, my first post...In looking over my "new" ride I have discovered that the rear has no fill hole...I can see a place on the center section facing from the front side, where a plug could be be.. but no plug..I have looked all over the center section and the housing...no fill plug to be found. I know nothing about Ford 9", but I guess that some center sections have fill plugs and some housings have a fill plug and I have a miss matched setup. Funny thing is I discovered this after replacing the driver side axle seal (because of lube all over the inside of the tire), my guess is that someone over filled the rear through the only hole I've found...the vent hole in the top of the axle tube...The old seal I replaced looked ok and when I pulled the axle no additional lube ran out??? I guess it leaked till it reached the correct level???lol..... Anyone have any idea's other than replacing the center section?? Sorry for the long post...........Chris

Originally Posted by 31rat

Ok, my first post...In looking over my "new" ride I have discovered that the rear has no fill hole...I can see a place on the center section facing from the front side, where a plug could be be.. but no plug..I have looked all over the center section and the housing...no fill plug to be found. I know nothing about Ford 9", but I guess that some center sections have fill plugs and some housings have a fill plug and I have a miss matched setup. Funny thing is I discovered this after replacing the driver side axle seal (because of lube all over the inside of the tire), my guess is that someone over filled the rear through the only hole I've found...the vent hole in the top of the axle tube...The old seal I replaced looked ok and when I pulled the axle no additional lube ran out??? I guess it leaked till it reached the correct level???lol..... Anyone have any idea's other than replacing the center section?? Sorry for the long post...........Chris

Some (most) of the 9 inchers have a pipe plug in the actual pumpkin itself rather than the back of the housing - left hand side. A 3/8" ratchet extension or in some cases, a 3/8 Allen wrench is used to take it out. This in mine is a tall SS aftermarket pipe plug - yours would be much shorter and may be painted or crudded over.

But to make life interesting, I believe Ford made some diffs w/o a plug in which case you need to pull the pumpkin out and weld a bung in the back of the housing and make up a filler. Or, fill it with a measured amount from the vent until you can "fix" it, one way or another.

Getting 180 weight threw the vent hole, thats going to be fun to watch.

I concur

180 weight - no way. 80 to 140 for a street driven vehicle

Thanks guys for the replys...Mine has "no" plug in the pumpkin...there is a boss where one should be?? If I put a fill in the housing would I just line it up with with where the fill should be on the pumpkin? The fluid level would be close? Any other input would be appreciated...Thanks, Chris.

Here, go to this site: www.kevinstang.com/Ninecase.htm


It shows your case with no drain plug.


Don

Pro70 that is a nice looking housing...who makes it? It sure looks strong. I went with a Mosier aluminum bolt through case which really saved on weight without sacrificing strength or so they claimed!

It's a Danny Miller Rear Gears Aluminum case, with 10 bolt pinion support, 40 spline M/W spool, 1350 yoke, Extra beefy caps & APR stud kit. 4:10 pro gear. And, last but not least, a blue anodized filler plug.

Originally Posted by pro70z28

It's a Danny Miller Rear Gears Aluminum case, with 10 bolt pinion support, 40 spline M/W spool, 1350 yoke, Extra beefy caps & APR stud kit. 4:10 pro gear. And, last but not least, a blue anodized filler plug.

They are a tough center section, and the blue filler plug must add at least another 10% on strength!!!!!

ooops. That should be 4:11.

Yup, Dave it should hold up to anything I throw at it.

Thanks Don, Thats what mine looks like..Could someone with the fill hole on the rear housing measure the distance from the bottom of the housing to the bottom of their fill plug and also the location side to side...I guess I will weld in a plug....Thanks.....Chris

Originally Posted by 31rat

Thanks Don, Thats what mine looks like..Could someone with the fill hole on the rear housing measure the distance from the bottom of the housing to the bottom of their fill plug and also the location side to side...I guess I will weld in a plug....Thanks.....Chris

Go back to my Post - #2. The centerline of the plug is the same as the center section stud closest to the camera lens (or pipe plug). If you are using an OEM diff, then measure gear oil by quantity, based on the donor vehicle - if you know where the housing is from

Thanks Dave; I have no idea yet, where the housing came from..I am going to try and get a close guess based on info. at the 9" web site......I think locating the fill hole in the rear of the housing lined up with the stud you mentioned will be close enough...Is the back of the housing center section cast or reg. steel welded in ??? Chris

It's steel.