There is a lot internet talk about bearing failure . Took the main drive gear out today the cage for the large bearing is made out of rubber I find that hard to believe . The kind of stress that bearing must be under

The needle bearings in side the main drive gear

 

Those spacers help wipe and trap metal slivers that the transmission is full of keeps it from getting under the roller and preventing it from rolling. Rollers work best when flushed with thin oil. Why Harley runs straight weight 50W gear oil in there. Since the bearings roll, as long as the material is hard enough, it does not take a super lubrication to prevent wear.

Years ago, transmission had huge ball roller bearings and parts were so hard, most things did not phase them. Modern transmission have much smaller bearings. Car transmission have greased bearings that have metal shields on them. Unlike a rubber seal on a sealed bearing, the metal seal keeps out trash but still allows the oil lubrication to get in.

Transmission I recently rebuilt with metal shields. That one with rubber is clutch out side one.

 

My manual told me to run 20/50 full synthetic oil in the transmission and primary mine is a 2010 Street Glide

 

I don`t think the failure has anything to do with the type oil that was used.

 

I agree but engineering says not to use a high detergent oil in s non filtered gearbox.
Harley around 2016 or so went back to Formula + as first choice in primary and transmission. Sure it was a direct result of number of warranty cases.

This failure was from quality control in the shaft I think. Slop and broken parts took seal.

Non detergent oil allow small wear particles to fall to the bottom rather then stay in suspension. This prevents long term wear

 

Well I don't mind being outnumbered but remember that there really isn't anything feeding oil to the bearing that failed. It has to work its way past another bearing and spacer to get to that bearing. Thicker oil, low temps and not letting the tranny get hot will slow down flow. One would expect that while the bike is on a side stand some fresh oil would flow in there..

IIRC HD still dumps Syn3 in the trannies on CVO bikes. On my 1000 mile service, the shop used Syn 3 in the tranny and primary.

 

Is that like a gear oil? I was reading on the internet for what that is worth that Harley found with using synthetic 20/50 with the oil being so slippery that the roller bearings were skating and not rolling like they should be . When the trans . starting leaking really bad the 20/25 syn coming out seemed thin like water . Why can,t Harley get anything right I have friends with Gold Wings with 200,000 plus mile al they do is change oil and put new tires . For the amount of money we have to pay for these bikes we deserve better than what we get from Harley . No wonder there sales keep going down every year

 

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I think you should go get a Gold Wing.

But first, do a google search for Gold Wing transmission issues...