Transmission main shaft

P

pedroeduardo

New member
Having done this twice---actually the dealer is doing it-- I am very interested what you find and if there is anything that can be done to keep it from happening a third time.


Tim
 
Just so I'm clear, you're inspecting the 8967 bearing, not the inner-primary bearing, right?



Is there any indication or speculation that perhaps the heavy gear oil some of us are using may be partially at fault? What are you using? Is there any concern the oil is not getting into the bearing? Redline claims its SPH flows like a 75w or better, yet protects like a grease, so I'm assuming there is no concern that the oil is a contributor. I think not since there is no common denominator as to oil used, and one reports using Syn3, another Formula+, and I used RL SPH.



I wonder if excessive belt tension might exacerbate this. I've always thought the aforementioned instance of excessive belt tension for a few K miles might've started the problem with my bearing. But if "fretting" is the cause why are we not seeing this in other years, at least not as frequently?



I was told by my tech that the bearing had not been upgraded and the replacement part used in Aug. '09 is the same one originally installed. He was not happy with that discovery and doesn't like the design of the "plastic bearing," as he calls it. In my case the plastic wall of this duplex bearing had come apart, and the tech thought that's what caused the bearing to fail since it had lost its integrity since apparently the wall holds the balls in. OTOH perhaps something else caused the plastic to fail. In 16k of riding with the noise one ball had fallen out and one or more had disintegrated leaving particles on the bottom of the tranny housing. Fortunately none became caught-up in the gears and damaged anything, as the tech inspected everything very closely before re-assembly.



If we could just get John at HD tech-support to weigh-in on this, as he would know. If there is an inherent problem with '07's I doubt if HD would admit it, as doing so would require them to address each problem that surfaces, much like the outer-cam-bearing issues seen in early TC engines. Since HD seems to be fixing at least some of these tranny-bearing problems in '07's even when the bikes are out of warranty, I'm thinking they know there is a problem and are addressing it. What concerns me is are they addressing the root of the problem and are not simply applying a band-aid fix by replacing the bearings knowing they will fail again in the future.
 
I know back in the 60's when the automakers were shipping there new cars across the country by train they attributed a lot of wheel bearing failures due to the rough tracks and them pulling the cars down with chains. The belt tension could affect this and could be caused by people using belt tension gages that are broke or way out of calibration. I use the proven push on it with my finger which has gotten stiffer over the years but is modified by lack of mussel mass HU, what'd he say, Ha!. Seriously oil flies all over the transmission even in neutral as long as the engine is running so it not the setting at red lights but the drive belt too tight or running too thick oil trying to make the transmission clunk may very well be a cause. Lets face it Harley's transmission clunks and that does not hurt it. Note transmission attachment showing neutral position and the countershaft gear spinning. Oil is high enough to catch main shaft gears also . There is also an oil slinger outboard in the end the clutch cable comes in.
 
I have an older softail (2002)but seem to have had the same or a very similar issue. My 5th gear main (5 speed) got all cheweed up and teh main shaft is all pitted from the gear walking on the main shaft.

I have run Redline shockproof for 40K the bike now has 52K. My mech attributes it to the Redline somehow although that does not make sense to me.

Drew
 
If anyone at the MOCO knows the cause of the problem they are keeping it a secret from all the dealers. No one at my dealership has any idea why this bearing has failed twice and they really don't seem to care they just like replacing parts.

Tim
 
My thought on this - especially with those who had work done and still had recurring problems. Is that HD's bearing supplies (within their parts network) are stocked with some of the older substandard bearings, and the recurrance rate is because an 07 that had a substandard bearing to begin with, is then replaced with another of the older design. It won't recurr with let's say an 09 - because they didn't have a bad bearing initially, and if they did, they very well could have a recurrance until the old stock is gone.
Also - I feel very strongly that the plastic cages do NOT contribute to this problem. As well the only places the balls ride on crossectionally, are the cupped races (inner and outer), and these cups are what holds the ball in place side to side, with the cages keeping the bearings apart axially.
 
Exactly the reason for my hypothesis! The Main drive gear and outer bearing 8967 are static at idle. With the clutch in or out. The vibrations from the engine pulses will cause the momentary loss of lubrication at the balls point's of contact on the races, leading to the Fretting condition I wrote about.
 
Pics as promised:

The races are pressed together during service. Also note the outer race (right) has had the hard chrome delaminated from the rough bearing track right, to the shoulder.


This is the inner bearing. The balls are pretty beat up, but not as bad as the outer.


Outer bearing. The cage could have been broken during disassembly. Note how pitted the balls are.


I just ordered this bearing from Zanotti, and it's back ordered from Harley, with a release date of 9-10-10. I wonder if it's a revised bearing???
Still working on the bearing supplier!
 
I was talking to a mechanic at the dealership about the 8967 bearing and his possible theory is there is no design or part problem at all. He thinks the amount of failures as compared to the amount of bikes is within an acceptable range. This would be easier to believe if it were not for some guys having more than one failure. I will be interested to see if there is a part number change after this back order is over.
Scorpion07 did the rep from *** ever get back to you?
 
I would agree, except that the bearing issues seem unusually high for 07's specifically. At least on the forum.

I haven't tried the rep since Monday. I have talked to a F.A.G. Distributor, and after searching for the bearing part number he concluded that Harley is the sole distributor of this bearing, and I'm sure F.A.G. is contractually bound to secrecy regarding any info about about it?
 
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