Transmission main shaft

A

ashleyb. :]

New member
Update--- I talked with my service writer at Eastside HD and they said the MOCO is going to pickup the tab on this tranny mainshaft bearing replacement part #8967 even though I am 5 months past warranty expiration date, and can you believe it Eastside has the bearing in stock. I am in shock. They also said I am the only bike they have sold in the last 3 years to have this problem. Why have I had the bearing failure twice in the last 11,000 miles. Who the hell knows but I would like an answer

Tim
 
That's great news. I was 10 months out and they covered it, but I reported the first indication of whine a year before that. My dealer said they had seen a few but that it was rare. I think HD's willingness to fix these indicates that it is a problem they acknowledge and are willing to make it right. The big question is how long will they continue to make it right if the problem persists? Based on reports here I'm not at all confident it won't rear its ugly head again.
 
Yeah after having this problem twice within one year I don't have much faith in it actually being fixed permanetlly. All I can do is ride it and hope. I really do like this bike and don't want to trade up afterall it is paid for and I don't want to start over on the payments and necessary mods for me to be comfortable

Tim
 
I am still very interested to hear what the people at F.A.G. have to say about the high failure rate of the #8967 main drive gear bearing.I think there must be more to it than just a bad batch of bearings.
 
I also eagerly await info from F.A.G. on this and hope they let loose with all the info they have. I'd like to know why the part is apparently the same on newer models yet most or all reported failures seem to be limited to '07's with a few '08's thrown in. I think we've established that build-date isn't a factor, which might suggest a batch of bad bearings that would congregate around a limited period of time, but since I'm an Oct. '06 build and someone else is May '07 this would seem a far-fetched notion.
 
That is why I suspect maybe there is no problem with the bearings and the problem lies with poor main shaft tolerances or transmission case alignment or something like that.
 
Still haven't received a callback from F.A.G. (No matter how many times I write that - it just doesn't sound right!). I'll give them another call today.

I'm still leaning towards bore misalignment.
When I pulled my compensator it came straight out (with the clutch and chain) without having to grind any of the inner primary in that area. In fact there was about 1/8" - 1/4" of room. I've read in the forum that it seems quite a few have to grind.
Also - 2 of the 4 roll pins are very loose in the inner primary - fall out loose.
This is a critical alignment, and to have it just slightly out whack would stress something in the assy.
I first started noticing a difference in my drivetrain at 20K (22K miles ago). Took it in - no problems. I'm thinking that's when the bearing "self adjusted" to accommodate the misalignment. Once it aligned it was just a matter of wearing out completely after that point.
In my case the Main bearing was the weakest link. Others have the Primary bearing go. But for some reason the incidence of the two needle bearing failures (inside the Main Drive Gear seems pretty rare. And even rarer still, is the trap door bearing.
I think it's a mechanical advantage that put's all the stress on the center bearing, in this case the Main Drive Gear Bearing.
I sketched up a rough idea of what I'm talking about:
 
For what it's worth the build date on my 08 ultra is Dec 07. I would have to agree with the above line of reasoning--just not enough beaarings for it to be a bearing problem but it must be some kind of alignment problem. This is what I first thought when this happened a second time--either the rear axle and the mainshaft are not parallel or the tranny case bore is not square to the mainshaft ?

Tim
 
What difference did you notice?



Thanks for the diagram, as that made the design of that section much clearer.



It would seem that given a misaligned bore the primary bearing would become as stressed as the center bearing. I've never heard of a trap-door bearing going out in these bikes. I can also see where a belt adjusted too tight might stress the center bearing more and cause a failure, and that was always my suspicion. I adjusted mine according to spec or slightly looser the night before leaving on a trip to TX, but when hot it became tight as a banjo string and I didn't have the tools to re-adjust during the trip. I started noticing the whine on the way back from that trip and it got worse in ensuing months.

BTW, does anyone know if this center duplex bearing is also called the "fifth-gear bearing"?
 
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