Tranny leak/ rebuild

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pan58head
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Joined: Mon Jul 16, 2007 12:26 pm

Tranny leak/ rebuild

#1

Post by pan58head » Wed Aug 08, 2007 6:00 pm

Hello All , I've been trying to fix some of the sins that my 58 has. I have a tranny leak out of the main shaft(real bad). I have changed the main seal twice , switched over to the end nut with the seal. Seem to get worse when I ride the bike (covers the rear wheel). I thought this was a breather problem which I stopped. My question is what is leaking ? I think it would be the bushing between the main shaft and the main gear that the sprocket sets on. I was planning on rebuilding the tranny this winter. Is this something I can do on my own, or should I send it out. I've rebuilt motors and transmission(auto) for years. Just new to PAINHEADS. I love my bike but it seems it likes my garage more the open road Later Bob



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#2

Post by Panacea » Wed Aug 08, 2007 9:26 pm

I went thru the same thing, the seal won't last unless the main drive gear bushing is within tolerances, as soon as I had a new bushing fitted mine quit leaking completely. I also had other issues, no end play on the main drive gear, so I couldn't tighten up the sprocket nut securely without puting a bind it. also loose studs that seeped oil. so It was a combination of things that lead me to doing a re-build. I had mine done by TCC MC. Mike

57pan
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#3

Post by 57pan » Wed Aug 08, 2007 9:27 pm

If you have done automotive engine and tranny work there's no reason you can't do a 4 speed H-D tranny - they're really pretty primitive and simple. There may be a couple of things you will want to have done by a reputable shop such as if you replace the main bearing outer race it will have to be line-honed to set up the proper clearance for the rollers. And you may want to have them set up the shifter forks after it's all assembled - or you can buy the special fixture and do it yourself.

Here's a link to my web site showing my tranny rebuild project a couple of winters ago: http://www.57panhead.com/ProgRept2-1.htm

There are three main sources for tranny leaks. The first is the main seal (the one that you have already replaced).

Then there is the bushing in the main gear where the main shaft sticks out. The original design did not address this very well but aftermarket gear sets include a lipped seal that presses into the main gear and seals against the main shaft.

Finally there is the clutch push rod sticking out of the main shaft. The early models had a cork seal that went in the clutch hub nut to seal this but you can get a replacement seal that is neoprene (or some such material) and you might even be able to put two of them in the clutch hub nut.

Also, don't overfill the tranny.

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#4

Post by fourthgear » Wed Aug 08, 2007 10:31 pm

Like was well said above , if you get into the tranny , you can replace the main drive gear with a later mod gear that has the seal for the main shaft. And it be true , if that main shaft bushing in the main drive gear is out of spec's it will go thru seals like no tomorrow and it won't care what kind of fancy sealing shit you put on there.
I rebuilt the tranny in my older Pan with a new REV TEC kit ( 2.60 close ratio )& it has the late mod. seal for the main shaft and no one will like to here this ,but I barely get a drip out of mine and I know because I measure it when changing fluid.

pan58head
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Tranny leak/ rebuild

#5

Post by pan58head » Thu Aug 09, 2007 5:32 pm

Thanks All for the resonse. I have all the seal you guys talk about including the clutch rod seal and super nut. 57Pan I went to your web site and discovered something, what is the purpose of the small "L" shaped piece of steal that goes in between the seal and the shaft. I don't have one of these could this be my problem. I replaced what was in there twice. I also agree that the cork seal is in the way. I alos see that you and forthgear are using rev tech gears any regrets? I just wanted to ride the old gal a little this summer . I already did the cosmetic rebuild now I need to tear into the motor and trans. Later Bob

57pan
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#6

Post by 57pan » Thu Aug 09, 2007 5:56 pm

pan58head, the little L shaped piece ensures that the hat-shaped piece rotates with the main gear. You don't want the main gear to be rotating inside the hat-shaped piece - it's not designed to do that (it's steel on steel with no bearings or bushings).

I have no regrets so far about going with the RevTech gear set.

fourthgear
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#7

Post by fourthgear » Thu Aug 09, 2007 9:58 pm

That would be the main drive gear spacer key and what it does in keep that main drive gear spacer turning with the main drive gear , so that it turns with in the main drive gear oil seal as apposed to the main drive gear turning with in the spacer ,which would wear both out instead of just the seal and or spacer. If its been running like this for an extended period , your main drive gear could already be worn and you will never stop that leak with a new seal. The pressure from the seal may cock the spacer and wear a grove into the machined surface of the main drive gear & spacer. The spacer is meant to wear out & be replaced many times more than the main drive gear , the seal itself will wear its mated surface on the spacer because of not just friction ,but road debris as well . When you are running at high way speeds you have some pressure inside that tranny and if it can find a path to leak oil, it will.

I have no problems with the REV TEC gears , great shifting and less noise then I'm used to.

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