Ball cap flange--gasket/no gasket?

[jab35]

Rebuilding my '26 coupe and found the usual gasket between the 4th main and the hogshead/engine pan end. It also had a gasket between the ballcap flange (p/n 2576) and the 4th main mating surface. I believe the only gasket should be the one to seal the 4th main to the transmission end, is this correct?

Mac's wonderful illustrations show a gasket between the flange and 4th main and my coupe had one in that location, although it is obvious that the driveshaft-differential assembly had been molested between the time it left the fatory and when it was parked in 1943. Thanks, jb

[speedytinc]

Your thinking is correct. no gasket between 4th main & drive shaft flange. its a ball joint, adding a gasket adds a lot of slop to that joint.
you can put a thin layer of ultra silicone to slow the drips of the melted grease & oil.

[Steve Jelf]

The Ford parts book shows only one gasket per car, and it's listed with U-joint parts (#2580). But I use it between the front ball cap and the transmission along with a smear of Ultra-Black. That's where you want to keep oil from leaking out of the transmission. For the rear U-joint cap I use the Ultra-Black only.

[TRDxB2]

Lots of contradictions in supplier pictures but owner info experience prevails and makes sense
"Is there a gasket on both sides of the 4th main? There should only be a gasket on the front, no gasket on the rear. If you have a gasket on the rear, it increases the gap between the rear cap and the ball, which allows more leakage." from http://www.mtfca.com/discus/messages/59 ... 1468619814

Supplier images /info contradictions.

[jab35]

Thanks, all: The Lang's illustration looks like the incorrect one in my old Mac's catalog.

And don't you just love those old forum posts where the entire thread fits on one screen. I have had little luck searching those old posts which usually hold the answers.