Removed gear set finally ,main drive needle bearing failed ,shaft ruined MD gear bearing also us will have to be replaced . Guessing a thousand dollars for parts and tools . Bike only has seventy thousand KL . Typically Harley putting cheap parts in and waiting for the aftermarket and owners wallets to fix the problems . From what I have been reading this a common problem with the six speeds

 

It's also a common problem with those who run the pepto in their trannies in cooler climates.

 

pepto?

 

Bismo. Shock proof,, The pink stuff.

 

I use redline in the tranny so I can see what is leaking. It is now about $20 a quart which is crazy price. Not sure what I am going to do. Buy in bulk if I can. I can afford it, but I hate letting someone **** me.

 

Problem was the shaft. Always going to be a weak point when there is no inner race. Quality roller bearings probably start with quality steel that only requires harding with heat, oil quench and then tempering at a lower temperature and another oil bath cooling to stress relieve.

That gear shaft requires case harding by a process in a furnace with out oxygen and the carbon is introduced with a gas added to the furnace. Takes time. And to get it deep, takes days. When ground, that removes some of the depth. Probably ended up with probably only .008 depth. It probably broke off leaving the soft underbelly whick you can see long ago and has been running like that till play overwelmed the oil seal. The gear teeth and such were supporting the run out.

Part of my first 4 year apprenticeship was a 3 month stent in heat-treating. I monitored 6 of theses furnaces. Some ran a week to get proper depth on parts. The rest of the time i spent loading air hammer tool ends in a furnace and manually dipping them in oil. Hot and dirty work from being covered in oil smoke.

We also had melted lead pots that we kept a layer of charcoal on top burning. We even hot oil bath treated delrin like the tensioner shoes in a Harley. Our shoes where mask guides for LA class subs.

None of the regular workers lived long after retirement. The boss that instructed me died an early death from lung cancer.

 

I know the main drive gear needle bearings had a reputation for moving out of position on some five speed transmissions, but I don`t recall any issues with the main drive gear needle bearings being an issue on the six speed gearboxes, has this been a problem on the six speed units?

 

It's been fixed in one way. When HD went to the 6 speed, they added a spacer between the bearings so is if one walked towards the other it would be stopped by the spacer.. DJL had the same issue with a twist gear setup in a 5 speed and I made a spacer for him.

Besides Ripsaws discussion about heat treat, another issue can also be using too thick of oil in cooler temps. The oil has trouble reaching that inner bearing. As I understand it was also possible on Evo 5 speeds where the tranny was not directly attached to engine. It took longer for the tranny to warm up. This stuff came up on on an old Yahoo mail list forum 20 years ago before all these fancy forums. There was a pretty sharp mechanic in Michigan (IIRC) that saw left side needle bearing failures as a pretty common issue on bikes using redline shockproof in the trannies. He had seen a few failures of the bearing and every one had been using the Pepto.

 

Also if you look at the 6 speed diagram, they use the spacer and a snap ring on each side to keep the bearings from walking.