Transmission Front Hub Leak

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    While waiting for my engine rebuild to progress, I decided to tackle a leak in the front of the transmission on my ’29. The trans leaks bad enough to have fully soaked the clutches. I sent them off to Fort Wayne last year, and everything came back absolutely beautiful. It is clear someone has removed the front hub before, and tried to seal the face between the shaft hub and the transmission with some form of Permatex. I called David Coco about how best to remove it (we were worried about damaging the mating surfaces). I tried a few things, and found carb cleaner worked great. I did a final clean by lightly sanding the surface around the radius of the hub with some emery cloth. It is not show quality by any means, but this car is still pretty much original. Now for the questions.

    Is there supposed to be a gasket between the hub and the transmission? Is there supposed to be a seal somewhere in the hub to prevent trans oil from getting out of the front of the shaft? When putting the hub back on, should I use some Ultra-black or something else on the bolts? Is there a gasket or flat crush or steel washer supposed to be on the bolts? Three of four had a flat and a lock washer, the last one had a thin piece of what looks like aluminum. Should the bolts be installed with safety wire? They have holes drilled in them.

    One last item. There is what looks like a Bakelite washer or shim between the hub and the bearing face. It was gunked up as well, but I cleaned it with a soft terrycloth for fear of ruining it. What is it, can it be replaced, does anyone reproduce them, or should I put it back and hope for the best?

    I am having trouble getting the web site to accept pictures, so I will post a few a bit later.

    Thanks for the help. Any suggestions are welcomed.



    Let’s try a picture now. Hub removed, not cleaned.


    I’ve reduced picture sizes and will try to post…..


    second picture


    third picture


    Thanks David. The original jpg files are about 4mb taken with a Nikon 5100 camera. We might have a storage issue with the web site. Is there any way to get a folder on the site where we can upload and share pictures? There are a number of threads that have great information and pictures, most recently William Lyons’ topic on the drum puller, but the site forces us to “dumb down”” the picture quality. The issue is likely the cost of storage…”


    A couple of non Pierce observations. The front hub arrangement is similar to what is on my Morgans’ Moss/ Jag boxes. They have a thin paper gasket, because the hub retains the front bearing and you can create end float if it is too thick. I can’t tell from your picture, but how is the front bearing retained? With the hub, a snap ring,??

    On the Moss box, the bolts have copper crush washers only, under the heads and are safety wired. The washers seal the bolts from oil leaks. You need to seal the heads not the threads. Aluminum washers work too.

    Any bolt that is drilled, I wire. It is too hard to drill them for no good reason. Also be sure the slot in the hub is pointing down and there is a corresponding hole in the case so the oil can drain back to the box.

    I was looking at the input shaft and it looked like it might have a scroll (worm) machined in it. I also didn’t see a seal surface. If it is a scroll, then the rotation of the shaft worms the oil back into the box and there may be no seal. Someone with a parts box might be able to confirm if there is a seal.

    I would guess that the washer matches one of the recesses in the hub? I would guess it is a spacer and is end float related.

    I have exhausted my guesses, conjectures and otherwise non Pierce specific observations. The are worth what you paid for them. Good luck.


    I have been meaning to ask the “Clutch Brake”” question. Is the fibre washer meant to be a clutch brake?? There is (From memory) a mention of a clutch brake in PASB 89-12 Page 9. Service note No.1-61 Dated 5-14-29 “”All engines after #601″” (I assume A-601)””equipped with a clutch brake””. It looks from your photos that the shiny rings on the gearbox side & on the 4 bolt flange which are the same size as the fibre “”washer””. If it is a clutch brake —-what thickness should the fibre washer be? It sure would make the changing into 1st gear when standing still with hot oil more like the Pierce adverts brag about & not a 10 second wait to avoid crunchy like mine is at the moment!!Knowledgeable Pierce Men please step forward. Cheers



    And I forgot to add—-Thank you Bob for saving me the trouble of a big dismantle job to see what is inside!!—Jak.

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