Modern Vespa

I noticed a bit of oil weep on the driven shaft inside the transmission of my 2006 LX150. The leak is minimal at the moment. But if the oil seal can be easily changed, it makes sense to do so while the transmission is open.

Can this oil seal be changed from the transmission side with the gearbox intact? I'm thinking like some motorbike clutch seals where you can pull out the old one with a drywall screw and then drive in the new one with a length of pipe.

Or is that doomed to fail, and this job requires removing the clutch shaft first (i.e. removing the exhaust, wheel, gearbox; new gasket; etc)?

I replaced it on my GT 200, no need to disassemble the gears. I drilled a small hole in the seal and screwed in the screw for pulling the seal from the block.

Thanks for confirming! It seemed like that would work, but it's great to hear an actual example.

Did you drive in the new seal with a piece of plastic pipe, or something like that?

I wrapped the critical front part of the shaft with plastic tape, then put oil on it and carefully inserted the gasket into the hole. It was quite easy, only with hands, no tools.

I replaced the oil seal today. As puno advised, I was able to pull out the old seal with a drywall screw. I used a Swiss Army knife reamer tool to make the small hole.

After lightly oiling the shaft and both surfaces of the seal, I was able to push the new seal in most of the way with my hands. Gentle tapping with a paint stir stick got it the rest of the way.

Good man.

Solid fix, thank you for the explanation and clear illustration.

Is the purpose of the wrapping to protect the lip of the seal as it's being slid down the shaft?

Does the seal have an inward- vs outward-orientation?

I wrapped the threaded part of the shaft to protect the new seal from rolling the inner lip when installing.

I wrapped the main shaft to prevent any nicks when making a hole in the old seal. I found a drill wanted to "skate" and I was afraid of damaging the shaft sealing surface. I ended up using the hand reamer as a safer option that actually did a better job here.

The seal has a cupped inner side and flat outer side. It's very easy to determine the orientation based on the existing seal.

Here's the inner side:

Oh, interesting. I see, it's just a seal. I had thought there was also a bearing in there.

A mechanic's pick works very well to pull the seal out. The set with the orange handles that harbor freight sells has a couple that are ideal for this.