Shovel tranny spacer mod

[Grumpa]

Stock 1969 FLH, leaking at tranny area more than the usual rear chain oiler amount. I tore it down, replaced:
The cork washer
35230-39 large seal between the case and spacer
12013A small seal between the main gear and mainshaft.

Assembled and after 30 miles or so leaked significantly overnight. Tore it down again and replaced all the above (on the theory that I might have boned it up somehow) along with the 35171-37 main gear spacer. Still leaks.

On teardown noted oil on the inside primary, on the inside of the sprocket, and notably on the splines. I filled up the tranny again, leaned it over and took this picture this morning:
IMG_0537.jpg

Research reveals I'm not the first one to encounter this issue and that one can modify the spacer to add an o-ring. Has anyone tried this modification?

[T. Cotten]

Grumpa!

The problem with an O-ring bandaid is that not only would the groove for it cut nearly through the spacer, it would have to ride upon a very, very narrow portion of the main drive gear to avoid either the splines, or the the relief next to the bearing surface. This would not allow you room to counter bore the spacer for a perfect endplay.

Face it, if you are leaking between the spacer and the gear, there must either be blemishes where they meet, or its loose. (Did you remove the sprocket?) Basically, leakage is the only warning if the sprocket comes loose in duty, and a band-aid O-ring would hide the problem until things get worse...

How did you hold the sprocket to torque it? (I use a piece of chain riveted to channel stock as shown in the attachment, ~75 ft-lbs if memory serves....)
Until it is fastened, it will undoubtedly leak, and the oil exposure will defeat any sealer. I fear you should thoroughly 'de-grease', and start over.

....Cotten

[Rubone]

What level of oil are you filling your tranny to?

[Grumpa]

Face it, if you are leaking between the spacer and the gear, there must either be blemishes where they meet, or its loose

Cotten, that makes sense. I must confess I thought the sprocket was tight enough (as tight as I could get it with a open end 1 7/8" wrench anyway) but I'll make the chain/channel fixture, break down and buy a socket, de-grease and try it again. If that doesn't work I'll replace the gear and mainshaft.

Here's a link to the modification I was talking about though: https://www.youtube.com/watch?v=Xsp238XVLgM

[Robert Luland]

Why would you replace the mainshaft and gear? I never under stood why people automatically just replace things and think things will get better. They don't! Unless you got some sprawling on the surface that the main drive gear rides on. I can't really think of any reason to replace it. Just for the hell of it I would throw it in the lathe between centers and check the run out but that's me. The main drive gear is one of my favorites. I have shoe box containers full of BT oem main drive gears that do not have a thing wrong with them other than customers demanded that I replace them even after clearly showed them there was nothing wrong with them. Look the clutch dogs are rounded off. That's not bad. In fact that's a damm good thing. It means the chips won't go back in your transmission. Well on my little rant, another thing that is good house keeping measure that I always do. If you have anything were a seal passes over a keyway slot. I always put a piece of Scotchtape over it. Keyways slots tend to be razor sharp and will ruin a seal's lip in a heart beat. If putting a slot and a o-ring in will keep more oil in your tranny and off your floor? I would do it! Bob L

[BigLakeBob]

The inner seal where it rides on the mainshaft in your picture doesn't look very uniform.

[T. Cotten]

I'm not impressed by the "better idea", Grumpa...

Its not a 'built-in leak' if they don't all do it.
And it seems like a tremendous liability to cut the spacer nearly all the way through, compress it under significant fastener stress, and then expect it to survive thousands of drive-train shocks.

Once again, I wouldn't use it because it would prevent relieving the spacer for a precise endplay (attached), as it would move the placement of the pre-cut band-aid spacer to where the O-ring would be off of the very narrow region where it could seat.
(Such techniques separate the "builders" from the "parts changers".)

Please inspect under magnification the shoulder of the gear, and the mating face of the spacer. Of course, relieving the spacer for precise endplay would also guarantee some control over its ability to leak, as you would be dressing it.

Let us know how it goes,

....Cotten
PS: Liberty stopped taking in new chassis accounts a decade and a half ago, so please, nobody ask....

[Grumpa]

What level of oil are you filling your tranny to?

For that picture I overfilled just to see where it was leaking. Leaned over and filled to plug level.

Normally I service the tranny with the bike level and just to the bottom of the plug with the same grade oil as the engine, in this case 20-50 conventional. Verified the vent is clear.

[Grumpa]

Why would you replace the mainshaft and gear? I never under stood why people automatically just replace things and think things will get better. They don't! Unless you got some sprawling on the surface that the main drive gear rides on. I can't really think of any reason to replace it.

I agree, just replacing parts isn't plan A. Right now we're only on plan C

But I have to say looking at the first spacer I replaced (plan B) the surface common to the large seal was pitted and I suspect that the mainshaft common to the small seal might be damaged as well.

I'm not ready to tear the tranny apart yet though, going to try your guy's suggestions first. The Scotch tape trick over the keyway is a good suggestion btw thanks

[Grumpa]

The inner seal where it rides on the mainshaft in your picture doesn't look very uniform.

I think it's just a bad picture on my part, that seal was installed with the Jim's installation tool which works pretty well

[Grumpa]

The inner seal where it rides on the mainshaft in your picture doesn't look very uniform.

Looked at it again today and sure enough the seal was a little cocked.

I suspect that my defensive perimeter has been compromised by ISIS operatives and I shall be having a word with the sentry, good eye Bob!