Drive shaft wear

[pancho]

We have all seen this,,





even a well lubed driveline and pinion cup show the contact of the pinion shaft and the driveline, and apparently this is as designed. Examining mine, I see that the driveline is wearing so that the pinion shaft is sinking into the driveline, being under compression from the spring. I am wondering if left to continue this wear, if eventually the pinion nut comes into contact, then even the outside edge of the driveline splines to the pinion cup?? This would certainly cause some extreme problems.  Do the damaged and dry shaft/pinion cups many have experienced show metal to metal contact on the outside edge of the shaft splines in the pinion cup?

[Rio Wil]

Thats why I was experimenting with this.....a felt washer saturated with lube......
not sure it helps.....or hurts......it has been in the pinion cup for 30K miles so far...
There does seem to be less "red rust"  ....

[pancho]

Well, there is no "red rust" on your pinion nut. I am starting to think that driveline wear may be measured not by the condition of the splines, but by the depth of the indentation, and the catastrophic failures may happen after the indentation is deep enough to allow metal to metal contact on the outside edge of the circumference of the spline and the pinion cup, or maybe just the pinion nut, with the resulting heat causing the symptoms we have seen. (red rust and spline failure) I may try something similar to what you did Rio, but with something like nylon sheet, like the thrust washer is made of, and maybe a less powerful spring. I need to make some measurements today, see how deep the indentation needs to be before the nut will contact, then the spline.

[indybobm]

I have noticed that each time I service the Final Drive, it is easier to pull the drive shaft out of the pinion cup. In another post I commented about one of the possible reasons to NOT remove the snap ring in the end of the drive shaft.

I think it might be the job of the snap ring to keep the end of the drive shaft off of the pinion cup nut. In my case the reason it is easier to remove the drive shaft is that the snap ring has lost some of its tension. If that is the case, it would not be able to maintain the position of the drive shaft in the pinion cup as designed. Or maybe the retention grove in the pinion cup for the snap ring has worn to the point where it cannot retain the snap ring.

Possible?

When re-installing the Final Drive, there should be a small gap between the Final Drive housing and the swingarm due to the spring on the driveshaft. If that gap is not there, the driveshaft might be pushed back too far in the pinion cup?

In the parts fiche, that snap ring is called the 'Stopper Ring'.

[pancho]

"I think it might be the job of the snap ring to keep the end of the drive shaft off of the pinion cup nut."

That thought was on my mind also, I looked for a groove in the pinion cup, that the "stopper ring" might snap into, but didn't find one. I am going to look further and do some measurements this afternoon.

[Tfrank59]

Yes I brought this up in my last post about the clip, and while there is definite hard contact between the driveshaft and the pinion shaft, it's not like metal chips are building up in there.  The driveshaft is a forging, and it's made to take that constant pressure and rubbing – it's actually work hardening in service – and I'm sure that the pinion shaft is also heat treated.  I haven't tried something like a felt washer soaked with moly paste, but I'm thinking some sort of flat bronze piece as a thrust washer might be an idea to try.  I think that since everybody's looks more or less the same with nothing else in there, then it's really not an issue.  My take is that it's probably better to leave the thing alone – not introduce any foreign parts that could get chewed up and cause more problems somehow – and just lube up the end of the driveshaft upon installation.  (And don't forget that those holes in the side that allow for some gear oil to get into the pinion cup must remain clear, and anything besides the OEM parts in there could obstruct those holes.)

[0leman]

Guess I am confused about this.  Doesn't the nut holding the pinion cup on turn with the cup and drive shaft.  Why should there be wear as they are turning at the same speed.  Wear could come from tension not been applied when the swing arm moves up and down allowing the drive shaft to bang into the nut.  BUT that is what the spring is for.  RIGHT???

[indybobm]

I think the spring is to push the u-joint toward the output shaft of the engine.

[indybobm]

Actually, there is something else to consider. Many of these parts are surfaced hardened to a certain depth. Once that layer is worn through, more rapid wear will occur.

[Ricky-D]

The spring on the drive shaft is to keep the universal joint in the correct alignment on the output shaft of the engine. The wire snap ring on the pinion end of the drive shaft

is to keep the shaft from falling (pulling) out when disassembling the housing from the swing arm. If you look closely at the spines on both the pinion cup and the drive shaft

you will see the contact of the splines is limited to the near end of the drive shaft because the splines on the pinion cup are not fully to the bottom of the cup. The wire snap

ring has no function to stop the drive shaft from reaching the pinion gear threaded end and you will see a polishing of the metal from just such contact which does no harm

or damage. That's why you can dispense with the wire snap ring.

[Daniel Meyer]

It touches. It doesn't wear there to any measurable degree. 210,000 miles on mine. Keep it cleaned and lubed at regular intervals and it will last indefinitely. Mine will be good for at least another 200,000.

No exotic lubes, mods, alterations, or theories required.

I'll see you on the road.

[pancho]

The wire snap ring has no function to stop the drive shaft from reaching the pinion gear threaded end and you will see a polishing of the metal from just such contact which does no harm or damage.

While this is true according to the measurements I took today,





it still leaves the question that the shaft of the pinion gear is steadily boring a hole into the driveline, and at an uncertain depth (I haven't figured that yet, but it won't be far because of the limited distance) the circumference of the end of the driveline will be in contact with the lip 1.675" from the top plane of the pinion cup and I am thinking that might be when the catastrophic failures occur.... "red rust"..??

I mean there have been many unexplained failures,,, something caused them...

Oleman,, there is enough play in that joint to cause wear... even a few tenths of thousands with the HP and torque applied to a part that size adds up to enormous pressures.

[pancho]

Well, I just found this picture in a post from Squealy on April 2013, and the outside circumference of the driveline does not show evidence of metal to metal contact, but then again, neither does the center where we know there was contact.

[Ricky-D]

Pretty evident the polished area on the end of the drive shaft in the center. The other part concerned is not pictured, and that would be

the end of the pinion gear shaft. The part that the nut threads onto and holds the pinion cup tight.

***

[John Schmidt]

Re. that snap ring on the end, Ricky is correct according to the techs at the Marysville plant. Some years ago I took a tour of the plant during a Honda Homecoming and asked a number of questions, the snap ring being one of them and its purpose. Their answer.....it's only there so facilitate assembly on the line, once it's put together it could be discarded without any problems developing down the road. I know most of us leave it in place(I being one of them), making it easier to remove/install the final drive and shaft as a unit. As for the indications of wear as originally posted, I do as Daniel does....clean it when taken apart and lube it properly. So far, so good.

It does beg the question however....since the drive shafts are from different providers over the years, could there be a miniscule difference in either overall length of the drive shaft or positioning of the spring. Just a thought, and I'd think the same would apply to the u-joint.

[Rio Wil]

Ricky.....to your point, here is a photo of a drive shaft mating surface and of the pinion shaft and nut.  It is clear to see that not only did the shaft wear off the end of the pinion shaft but also contacted the surface of the nut. The six sided nut is clearly worn into the end of the drive shaft about .010-.015 thou. There was no other reason to replace the shaft and pinion cup in this instance except for the wear. It is also evident that the end of the drive shaft only contacts the end of the pinion shaft (and nut) and no other place inside the pinion cup. As a matter of course, I leave the snap ring installed for whatever reason....

My mystery is: for 3-4 maintenance intervals the splines will look great, well lubed with grease (and not from the final drive fluid) for 45-60K miles, then the next interval (15K) it will have eaten itself!!!!
I am on my 4th set of shaft/cup.....glad the are only about $80 a set......

The rearward pressure the drive shaft exerts on the pinion shaft is from the spring on the front of the driveshaft where it enters the ujoint. When mating the final drive to the swing are, the amount of spring compression is evident when the drive is almost fulled mated....about 1/16 to 1/8 inch compression of the spring. That doesn't seem to be a lot of pressure but there is evidently other forces acting to exert significant contact to induce abnormal wear (aggressive acceleration-high speed driving-aggressive gear shifts.....)..

Eating a shaft/cup set every 60K miles or so is tolerable.....but it is curious why some never have a problem...

Just to be clear, I don't believe the "red rust" to be from water intrusion, but from the contact of the drive shaft/pinion shaft and generating enough heat to bake the lubricant to the point it starts to grind off tiny metal particles and left to continue it will creep out to the splines of the shaft/cup and eventually produce the results pictured in another post below..... just my .02......



[imghttp://i783.photobucket.com/albums/yy111/wncbridges/P1010825_zpsgucmdryi.jpg]http://[/img]

[Mallett]

Looks to me like some of y'all have packed so much grease up in there that the final drive oil can't do its job of lubing the cup & shaft... .....mine is sloppy wet every time I pull it out...

[Rio Wil]

That is pretty much what this is all about, after following the "Honda lube protocol" we still ate shafts and cups so we launched off into other solutions.  That might be a worthwhile survey to see how many have opened the shaft/cup and found any evidence of final drive fluid....

[pancho]

I have learned this much,, the depression from the pinion gear shaft, in my drive shaft is .022 deep.



If allowed to continue for another 70-80 thousands, both the nut and (in my drive) the outer circumference of the drive line will both have metal to metal contact. If that would cause the observed meltdown of those part, I don't know, but I will be monitoring the depth of wear in the drive line every time I take it apart in the future, and be molying up those surfaces. I may make a nylon bushing and give it a try, but on a new drive line.    Rio, I wonder if that drive shaft that the nut had contacted, how deep was the depression from the pinion shaft? and was this a case of red rust when disassembled?

Never mind on the red rust question Rio, I guess the picture of the cup is the one involved.

Also, in my opinion, the only time you will get gear oil into the pinion cup is when the final drive is overfilled, and that the holes in the pinion cup are for pressure equalization.

[pancho]

Well, looking at that picture of Squealys' again, it looks like his shaft wore to the point of the nut having contact in the cup.

[Rio Wil]

The depression in the drive shaft is about .070-.080 deep......the drive shaft with the nut impression is the shaft that wore the pinion shaft. The cup in the photo full of grease is a new one that I checked at 5K miles to see how it was doing, the new drive shaft with 5K miles on it is laying on the work bench.  I also put the felt washer in with this drive shaft and cup at the same time. This shaft/cup/felt washer combination has about 30K on it so far.   

[pancho]

When you disassembled the joint with the shaft that is worn from the pinion nut, was it all dried up and destroyed,, "red rust"?

[Mallett]

That is pretty much what this is all about, after following the "Honda lube protocol" we still ate shafts and cups so we launched off into other solutions.  That might be a worthwhile survey to see how many have opened the shaft/cup and found any evidence of final drive fluid....

+1...I've serviced mine 6 times in the 75,000 miles I've put on my Valk...sloopy wet with final drive fluid every time.....

[Rio Wil]

Yep.....that drive shaft/cup was changed due to looking like Squeakys photo at a a5L inspection.

Mallett:  I have serviced mine about 16-18 times at 12K to 15K intervals......3 times it had eaten itsself. I have talked to a number of GL1500 GW owners that have a blank look when asked about how often they do spline maintenance. Something about that final drive that lubes the way it is supposed to......means you never have to do it, just change final drive fluid occasionally......what a dream...

[pancho]

Well, I'm starting to think we can prevent the failures by 1. keeping the joint well lubed with Moly grease (2 grams into the cup and 1 gram in the shaft splines)  as per Honda instructions, and   2. monitoring the depth of the bore in the drive line caused by the pinion gear shaft, and replacing the drive shaft when the depth is approaching 70 thou or so,,, before the nut contacts the shaft. Number 2 will be added to my final drive maintenance list.  When I do need to replace the drive shaft, I'll look into a thrust washer, in the mean time, any way to keep moly on that spot as you are attempting Rio, can't do anything but good.

Check out the depth of the hole being bored in your drive shaft when you are in there guys,,, see what you think.

Rio, you said 

" It is clear to see that not only did the shaft wear off the end of the pinion shaft but also contacted the surface of the nut. The six sided nut is clearly worn into the end of the drive shaft about .010-.015 thou."   

I'm thinking and seeing that that it is the opposite happening, maybe a bit of both,, I see that the pinion gear is harder than the drive line at that point and pinion gear shaft is boring a hole into the drive line until there is contact with the nut.

[Mallett]

Yep.....that drive shaft/cup was changed due to looking like Squeakys photo at a a5L inspection.

Mallett:  I have serviced mine about 16-18 times at 12K to 15K intervals......3 times it had eaten itsself. I have talked to a number of GL1500 GW owners that have a blank look when asked about how often they do spline maintenance. Something about that final drive that lubes the way it is supposed to......means you never have to do it, just change final drive fluid occasionally......what a dream...

Rio Wil, I service mine at 10k intervals....so far no problem with the spline or cup...What I do is put a thin coat of CV joint lube on the spline & inside the cup with a brush & then reassemble it...

[indybobm]

Rio, does this picture show that the end of the pinion gear shaft itself is being worn away? I can understand monitoring the wear on the drive shaft and replacing it when it gets to a certain depth, but the pinion gear shaft seems to be eaten away also. At what point do you replace the final drive also.

In an earlier post I suggested that the ring and pinion gear are surface hardened to a specific depth. When that thickness is eventually worn away, the wear would be at a much faster rate.

Any thoughts on this?

[Ricky-D]

Rio Wil, I certainly agree with you that the wear you pictured is extreme and abnormal, and not something that should be expected.

I can visualize several scenarios where this might occur and they all start with contamination. This is the main reason for the seal

between the shaft and the pinion cup. Of course, the only reason for my post was the unnecessary needing to replace the clip to which

is evident the clip would not prevent the wear you have pictured.

***

[pancho]

One final thought I had on this,, while sanding my saddlebag and lid,, as the steel is steadily being removed from the drive shaft, where is it going? It is not getting hot enough in there to turn it into vapor, so if there is no gear oil in the cup, it is being deposited in the grease that was used to lube the joint. I theorize that when the wear is extreme enough to cause the nut to contact the shaft, (or maybe even when the load of powder in the grease gets extreme and causes friction) then there is enough heat generated to boil off the carriers in the grease and what is left,,, the solids including a LOT of steel powder by this point.. steel or iron powder exposed to heat causes it to join with oxygen in the air, iron oxide.. red rust... which is also abrasive and if left will certainly completely destroy the joint.

[pancho]

"Eating a shaft/cup set every 60K miles or so is tolerable.....but it is curious why some never have a problem..."


Maybe it is that some, like me, never really cleaned the drive line and pinion cup correctly on disassembly,, many times just added more moly grease, and some who actually have been cleaning the parts.

It seems that if the parts are not cleaned, you are making a grinding compound in the end of the drive line that just gets more concentrated with time and will accelerate the boring into the shaft.

I think I'm going to clean up that area when in there from now on.

[Tfrank59]

That's right, if you don't clean parts and just add more grease, you are just making a kind of lapping compound. Problem is it's very hard to clean those internal splines completely, even with parts washers and all the right brushes – I did it yesterday on my spare pumpkin at my place of work where they have all kinds of parts washers and parts cleaners and it still took me 20 minutes.

[pancho]

If you remove the pinion cup, it's fairly easy, just a toothbrush and a tilted tub with a solvent (gas, lacquer reducer, diesel, whatever you have) in it.

[Tfrank59]

I was talking more about the drive splines than the pinion cup..

[pancho]

Gotcha Tfrank,,, keep in mind that the splines and flange joint, if kept maintained with moly paste, good condition o-rings, and a thrust washer, does not have the problem of metal to metal grinding that is depositing the debris as in the pinion cup joint. I believe it is much more important to clean the pinion cup/drive line joint thoroughly when disassembled, than it is the flange/splines joint.. I will continue to clean the flange only and add moly paste to that joint,,, I agree it would be a real PITA to completely clean the splines every time the rear wheel is off.

[The emperor has no clothes]

Gotcha Tfrank,,, keep in mind that the splines and flange joint, if kept maintained with moly paste, good condition o-rings, and a thrust washer, does not have the problem of metal to metal grinding that is depositing the debris as in the pinion cup joint. I believe it is much more important to clean the pinion cup/drive line joint thoroughly when disassembled, than it is the flange/splines joint.. I will continue to clean the flange only and add moly paste to that joint,,, I agree it would be a real PITA to completely clean the splines every time the rear wheel is off.

I used to clean mine out the best I could with Q-Tips and rags. After watching Grumpy clean it all spotless with a parts washer and not having one myself. I started using the cheap cans of spray carb cleaner with good results. 

[gordonv]

My only concern with cleaning the cup with any kind of liquid cleaner, is for that stuff or the dirty "oil", going through the holes into the rear diff.

Thinking it would be best to remove the cup and clean it out fully away from the diff.

[pancho]

I agree with you 100% gordonv, you never want to wash any of the debris from the pinion cup into the final drive,, best to remove the cup for cleaning. I believe meathead was referring to the splines that the flange goes into.

[The emperor has no clothes]

I agree with you 100% gordonv, you never want to wash any of the debris from the pinion cup into the final drive,, best to remove the cup for cleaning. I believe meathead was referring to the splines that the flange goes into.

Yeah I didn't phrase that very well. The pinion cup is easy enough to clean out with a rag. Then I blow out the  grease that gets stuck in the 2 holes.

[Rio Wil]

Rio, does this picture show that the end of the pinion gear shaft itself is being worn away? I can understand monitoring the wear on the drive shaft and replacing it when it gets to a certain depth, but the pinion gear shaft seems to be eaten away also. At what point do you replace the final drive also.

In an earlier post I suggested that the ring and pinion gear are surface hardened to a specific depth. When that thickness is eventually worn away, the wear would be at a much faster rate.

Any thoughts on this?

I think you are right about the drive shaft and pinion shaft being surfaced hardened, but I also think those parts are probably forged which adds toughness (I think...but I am no expert on that).

After replacing the shaft and cub and installing the felt washer, there doesn't see to be any addition wear on the pinion shaft.  As a matter of fact, it is interesting that the forces acting  on this point of contact are not sufficient to tear the felt up,  the primary force being thrust and only very little squirm of the two parts, just what the spline tolerances allow. Anyway, I don't plan on replacing the final drive for this issue. With the felt there, there is no contact

Mallet.....just curious, are you the gentleman that gets like 27K from a set of tires.  Not asking to be pissy, just wondering maybe about riding style and drive shaft/cup wear.....any correlation?

I am thinking at the next lube interval, I will weigh up the recommended amount of moly and clean up the cup to spotless (as I always do) and give it another go....maybe overfill the final drive by maybe .5 ounce and see if it will lube the splines.......ain't holding my breath :crazy2:h......

[Mallett]

Rio, does this picture show that the end of the pinion gear shaft itself is being worn away? I can understand monitoring the wear on the drive shaft and replacing it when it gets to a certain depth, but the pinion gear shaft seems to be eaten away also. At what point do you replace the final drive also.

In an earlier post I suggested that the ring and pinion gear are surface hardened to a specific depth. When that thickness is eventually worn away, the wear would be at a much faster rate.

Any thoughts on this?

I think you are right about the drive shaft and pinion shaft being surfaced hardened, but I also think those parts are probably forged which adds toughness (I think...but I am no expert on that).

After replacing the shaft and cub and installing the felt washer, there doesn't see to be any addition wear on the pinion shaft.  As a matter of fact, it is interesting that the forces acting  on this point of contact are not sufficient to tear the felt up,  the primary force being thrust and only very little squirm of the two parts, just what the spline tolerances allow. Anyway, I don't plan on replacing the final drive for this issue. With the felt there, there is no contact

Mallet.....just curious, are you the gentleman that gets like 27K from a set of tires.  Not asking to be pissy, just wondering maybe about riding style and drive shaft/cup wear.....any correlation?

I am thinking at the next lube interval, I will weigh up the recommended amount of moly and clean up the cup to spotless (as I always do) and give it another go....maybe overfill the final drive by maybe .5 ounce and see if it will lube the splines.......ain't holding my breath :crazy2:h......

Rio Wil, I get 17-19k out of a Avon Cobra bias ply front tire...I'm darkside on the rear...my riding style would be considered aggressive...



Guys I use carb cleaner to clean out my pinion cup....I wait until after I get it cleaned & then I tilt the pumpkin & let the final drive fluid drain out the little holes...I put a lite coat of CV joint lube (6% moly) on the splines & inside the pinion cup...back together she goes...sloppy wet with final drive fluid every time I service it...BTW I don't overfill with fluid...