Final drive issue?

Kneebyter

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Checking my rear tire pressure tonight and the back of my hand came away with oil on it. It came from that small rectangular hole in the plastic ring right next to the rear wheel. I put my finger in the hole and came away with more than just a few drops.

The oil was very black, and appears to have been dripping onto the wheel and tire, but only while moving, judging from the shape of the spots on the tire. I examined the garage floor where I park and there is no evidence it has leaked while sitting there.

I checked the fluid and it is low. That got me thinking that I don't remember the last time I checked it. I went to my maintenance records and, although I think I remember changing it, I can't find a record of it (which would be very unusual for me). I bought the bike with 1500 on it, and it now has almost 16K on the odometer, so if it hasn't been changed I'm a little worried.

I am going to try to change it this weekend, and collect what drains out just to see how much is there.

I seem to remember someone else mentioning that they had fluid coming out here but couldn't find it in a quick look at the forum. Any ideas? If the oil has been in there for 14K miles, is it possible it just thinned out and is getting past seals because of that?

20151006_213920.jpg
 
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It may be throw-off of graphite grease from the splines. Has the weather there been very hot? It is unlikely, but possible, that you have a leaking diff seal. With low Miles on the clock it would be most unusual for a seal to leak. If it was mine I would remove the rear wheel and have a close look inside. At 16K the splines should be cleaned and regreased with the "special" grease anyway.

Macka
 
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Kneebyter

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I thought about that, but it had the same consistency as the oil in the final drive. Wouldn't the splines have been cleaned and greased when I had the new tire put on 7K ago?
 

tawilke46

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I thought about that, but it had the same consistency as the oil in the final drive. Wouldn't the splines have been cleaned and greased when I had the new tire put on 7K ago?
That is correct the splines should have been lubed with Moly when the rear tire was changed. But that does not guarantee that it was done. Just ask Phil......
 
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Kneebyter

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Good point, I remember reading that thread.
 
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Like you mention, any excess grease will have a completely different feel than gearbox lube. Sounds like you need to remove the wheel and see if the seal is leaking. I forgot, is there a level indicator hole? If so you can pull that plug and see if the level is up enough.
 

tawilke46

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Yes, there is a fill hole on the differential housing. With the bike level fill the reservoir with appropriate weight gear oil to the bottom threads on the fill hole.
This would also be a good time to get a flashlight and inspect the gear teeth wear while rotating the rear wheel.
 
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And, if you do drain and refill, carefully inspect the magnetic drain plug and the drained fluid for any signs of metal content.
 
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It's overkill, but I suggest changing the final drive oil when you change the engine oil. It doesn't take much oil, it's easy to do, and you always know you have fresh oil there.
 

Phil Tarman

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Plus 1 to John's suggestion. It's easy to do and, like he says, not very expensive. It's just not protection against un-Honda-Moly-60'd splines.
 

DirtFlier

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I do my own tire changes so remembering to grease the driven splines is not a problem but I'd guess that at least half the time, a dealership will not grease the splines. And if they do remember, do they use Moly 60 or normal grease? Another potential problem is with the projected long life of modern tires, the splines might go dry before you get to the next tire change.

Kneebyter - if it's Moly 60 grease on the outside of the final drive case, once on your fingers it doesn't want to come off because of all the graphite. And if it's normal grease, it comes off easily without staining your fingers.

I wear rubber gloves when applying Moly 60! :smile:
 
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You do that each time you change the rear tire. If you do the entire drive shaft/U-joint servicing each year, regular GAA grease will work, but the moly goo sticks better.
 
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HAT

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Kneebyter, had same thing on my NT at a little over 14K miles. I let it go for awhile with no real issue other than a bit of oil would spread around the rear wheel and collect dirt. Just a little bit of gear oil added - no drastic drop in oil level. Did find a wee bit of dripping onto the rim and tire when the bike sat after riding, esp. longer rides. Was going to pull it apart myself, but didn't have time and didn't want to have the bike down if it took me awhile to complete the job.

Took it in to the local independent cycle shop I use for some ervice and they found the final drive inner seal leaking - the "large" final drive output seal still appeared to be OK. The parts - seals, washer, o-ring - were about $28 (shop), gear oil and misc about $40, and about $200 labor. Also lube splines with 60% Moly while they were in there. Good news is no leaks since the repair over the last 6k+ miles.

I have part numbers if you need them. Or shop drawing can be found here:
http://parts.southernhonda.com/a/Honda__NT700V/55179671__6264467/FINAL-DRIVEN-GEAR/14MEWA01_MEW4F1600.html
 
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Kneebyter

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First, thanks to everyone who replied. I have been so busy that I just got the wheel off today. It appears to my untrained eye that the black seal just outside the splines is the culprit.

Is it pretty straight forward to take the pieces out, replace the one bad and put it all together again? Or is this something better left to a professional? If it is the latter, maybe I could just detach the shaft housing from the swingarm where the four nuts are and take just that piece to the shop. I already have most of the work done that takes time, so it would save me a bit at the shop.

Thanks for all the help.

Tim

Strangely, it appears that the picture is upside down after being uploaded, but you get the picture (pun intended).
 

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Woodaddict

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I think that looks like moly60 which is all over the splines, tire hub and final drive hub. not final drive fluid
 

DirtFlier

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I agree that the excess appears to be Moly 60, which is jet black in color. Someone may have applied way too much of that stuff.

Whenever I grease the drive & driven splines, I first start by wiping off all the excess that has been flung off. I then apply Moly 60 to the driven flange (on the wheel) teeth using a solder brush and only enough to fill the valleys of all the teeth but NOT beyond that. The S/M gives a gram value for how much grease to apply but who has a gram scale in their garage? :)

ps. wear plastic, throwaway gloves when dealing with Moly 60!
 
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While I agree, that looks like moly grease, not oil from the box, and the outer seal looks good, but, what about that central shaft alignment. I hope that is due to the camera angle and not because a bearing inside has become toast.

And, that looks like a LOT of moly grease. Like above, I keep reducing the amount I use on the splines. Do make sure you clean all the old stuff off. When applying I just use some rubber gloves and use a finger to wipe it on the teeth of the wheel. You don't need that much.
 

Woodaddict

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that central shaft is a spacer that can be taken out, about 3 " long
 
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Agree that it looks like an excess of Moly 60. If it were mine, I'd clean it all up, apply just enough new Moly 60, change the oil in the final drive and ride it for awhile to see what it does.
 
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