Final drive noise

[davit]

https://youtu.be/_nn8_moADLA

I'm not even sure where to start.  It sounds to me like it is coming from the drive gears, not the bearings.  I removed the bolts from the case but it appears to also be sealed with a rubber sealant.  What's the best way to split the case?

[Bighead]

It shouldn't be sealed with sealant. Or at least the three I have opened up were not.

[hubcapsc]

There's for sure goo inside the final drive. The manual talks about what
kind to use. My (now pictureless) write up on final drive refurbishment
has the kind I used listed, along with the comments of others about it...



-Mike

[davit]

https://youtu.be/vHsLK8yW_MY

Think I found the problem, the inner race on the input shaft bearing is loose.

[indybobm]

Did it make that noise before you took the pinion bearing adjuster out?

[davit]

Did it make that noise before you took the pinion bearing adjuster out?

Pinion bearing adjuster?  I have a pinion cup and nut, am unaware of a bearing adjuster.

[davit]

I just looked at a parts diagram, you must be referring to the bearing retainer.  The retainer sits on the outer race, it's the inner race that's moving.

[indybobm]

Same question.  The inner race is actually two pieces . If the bearing itself is not positioned properly by the retainer, the inner races will be loose. See the picture on page 12-12 of the service manual. The retainer is torqued to 112 ftlbs when installed.

Page 12-12

[indybobm]

I listened again to the first video that you posted. Sounds like the ring gear and pinion are meshing too tightly. Maybe the big gear (Item#27) has failed.

[Ricky-D]

No, I don't buy that!!  With such a small amount of turning making such a noise I would necessarily think the noise is a bearing that is on the power input shaft.

With the unit disassembled, it's easy to closely inspect the races and the bearings for damage. I'm thinking it's the large bearing since that would be first in line to be contaminated from crap coming down from the pinion cup.

***

[indybobm]

I have had a number of Final Drives apart doing the GW Spline swap.
One of the first that I did I decided to try to put the GW Ring Gear along with its bearing and spacer into the Valk Final Drive just to see what would happen.
When the gears were turned, it made the same exact noise as the first video that davit posted.
I found that I had no backlash in the gears because the spacer was thicker on the GW Ring Gear and was forcing the gears to mesh too tightly.  Replacing the GW spacer with the Valk spacer stopped the noise. Of course, I did NOT use the GW Ring Gear, just swapped the splines out.

[davit]

Thanks for all the help!  The noise was coming from the pinion bearing.

I did open the case up, took a few good whacks on a slim prybar to break it apart.  It was gooped up like in hubcapsc picture.  The gears looked brand new.

Indybobm's picture and description of the split inner race threw me for a loop.  Honda shows a one piece bearing when looking up parts on ProCaliber so I was under the assumption that the bearing was failing.



So this is where it gets good.  I had contemplated not sharing this because it makes me look like an idiot... 

5,000 miles ago I replaced the driveshaft and pinion cup.  Spun pinion cup nut off with a new-to-me impact driver, spun it back on with same.  Apparently it stayed tight for 4,998 miles and before working it's way loose... 

After thinking about it all night (more like stressing, I need to ride that bike) I put a channel lock pliers on the pinion cup and spun the nut back on, put it all back together and took it for a ride around the block, then a ten mile ride. The noise is gone!

So evidently the pinion cup nut sets, and holds, the inner race where it belongs.

[indybobm]

Glad it was simple. Loose pinion nut allowed the pinion gear to move toward the ring gear eliminating the backlash. Made the gears mesh too tight.

[pancho]

If you are going to be working on that stuff davit, you may want to make some kind of rig to get an accurate torque reading on the nut. I drilled holes to accept the driven flange and brace the final on a table,, I have seen other ideas from others.

[hubcapsc]

I made this overly complex machine to overcome the pinion cup nut problem.



When you attack the nut, you have to deal with three degrees of freedom:

- spinning the nut
- spinning the ring gear
- spinning the whole final drive

I busted the machine to flinders trying to loosen an overly tightened
pinion cup nut - one that had been removed and replaced with my
buddy Dan's studly impact wrench... "How tight should it be?"... I
didn't know... "Tight!"...

Anywho... next time I need to do it, I'll use a 16 foot long treated yellow
pine 4X6... seriously. Drill holes for the flange pins on one end
of the 4X6. Set the flange in the holes. Set the final drive onto the flange.
Loosen (or tighten with your torque wrench) the pinion cup nut. Only
if the pinion cup nut is too tight will the entire leveraged 16 foot long
4X6 spin like a clock dial when you apply pressure to the pinion cup
nut, and you could hold the far end of the 4X6 if that happened.

Some kind of heavy shop table would be even better, but who wants
to drill holes in that? Perhaps holes in a small board held by the nice
vise on your heavy shop table... 

-Mike "I don't have a shop table"

[indybobm]

Good advice, you never what torque value you are getting with an impact wrench. With an impact wrench, the whole unit takes a pounding.