Lateral play gearbox output bearing

[Tinus89]

Hi all,

 

During maintenance (greasing the driveshaft), I discovered the driveshaft was pushed over the normal mounting position on the gearbox output splines. Most likely hydraulic lock or sticking (due to barely no driving in the last two years, house renovation) has pushed the driveshaft further onto the splines.

I also noticed my output shaft seal to be leaking a little (but it can also not have been installed deep enough, but I did not have a tool at hand to drive it any deeper), but also discovered my output shaft to have approx 2-3mm axial play. There is no lateral/radial play and also no notchyness in the bearing.

Here is a video: https://www.youtube.com/shorts/74sLrz0mv6A

Anyone who can tell me whether this is too much play?

And if it is, can I replace that bearing with the gearbox on the bike or will it have to come off?

[docc]

I suppose I would call that "axial" play rather than lateral (side-to-side). That much side-to-side (lateral) play I would call trouble. I doubt what you are showing is a problem, but defer to those who know this gearbox from the inside . . .

[Lucky Phil]

Normal.

 

Phil

[Tinus89]

Thanks for the comments and comforting!

Just for the record, I have always learned it like this (at Mech. Engineering uni):

 

[Lucky Phil]

9 minutes ago, Tinus89 said:

Thanks for the comments and comforting!

Just for the record, I have always learned it like this (at Mech. Engineering uni):

 

Nothing to do with this. The bearing floats in the rear housing by design.

 

Phil

[Tinus89]

What I meant by that picture is explaining how I learned which direction is axial and lateral/radial

[docc]

5 hours ago, Tinus89 said:

What I meant by that picture is explaining how I learned which direction is axial and lateral/radial

Seems I was using anatomical terms instead of mechanical.

[gstallons]

It ain't good , whatever it is .

[guzziart]

FWIW, I call it "end play".  

While the end play might be acceptable as Lucky Phil said, I thought it was unusual for the seal to flex in and out as the spline shaft is moved fore and aft.  I don't think the seal should be hanging up on the shaft and wonder if that is where T89's leak is coming from....a failed seal, seal lip riding in a dirt groove/rust/etc. imho but defer to the more knowledgeable here.

Art

Update an hour later: OK, I've got the same movement on mine as in the video and no leaks.

 

[MartyNZ]

I can pry the forward UJ through openings in the shield, to pull the gbox shaft in and out almost 2mm. It needs a lot more than hand pressure.

I expect that all the suspension movement that loads the driveshaft in rapid compression/tension is all taken by the sliding joint in the middle of the shaft. It would be a disaster if the gearbox is exposed to suspension movement. I'm going to give all 3 nipples another squirt of grease to make sure.

[Lucky Phil]

1 hour ago, guzziart said:

FWIW, I call it "end play".  

While the end play might be acceptable as Lucky Phil said, I thought it was unusual for the seal to flex in and out as the spline shaft is moved fore and aft.  I don't think the seal should be hanging up on the shaft and wonder if that is where T89's leak is coming from....a failed seal, seal lip riding in a dirt groove/rust/etc. imho but defer to the more knowledgeable here.

Art

Update an hour later: OK, I've got the same movement on mine as in the video and no leaks.

 

It's not hanging on the shaft. You are seeing the dust lip part of the seal riding on the chamfer of the output spline seal running surface. The oil seal lip is internally behind that and not visible.

 

Phil

[Tinus89]

Phil is correct, and I also noticed this. So I took a seal driver and drove the seal 3mm deeper into the gearbox case, causing the dust lip to now also remain on the sealbore on the shaft.

I did order a replacement seal, but will keep this on stock for now as it was more of a wheep than a leak. Thanks for all the comments!