A555 Main Shaft Race Issues

[bfarroo]

So I pulled the trans apart for the CSX and immediately noticed the input shaft was way out of spec. I pulled it apart and set the main shaft and gear set aside and covered it with a clean rag. I got the new bearings and races installed for the input shaft, set the clearances and went to put in the main shaft today and notice this.



any ideas what could have caused this? The main shaft bearing looks and feels good so now I don't know what to do. I'm going to put a spare A555 I have in and run it with that for SDAC. Is this repairable or should I be looking for a new main shaft? What main shafts will work? the trans is an 89.

[turismolover22]

If you take it to a competent machine shop you can do one of two things.A - TIG/Spray weld new metal on, treat it, and regrind it to spec, just like a damaged crank.B - They probably could grind it down and sleeve it back to spec.Looks like a piece of debris got in there, or your Koyo isnt in the best of shape.

[135sohc]

It is a crappy design to run the roller elements straight on the shaft surface. NPG figured out 25+ years ago it was a failure point and hence the 523/568 using a proper inner race.

[cordes]

I would get a new shaft or have that one repaired. I don't know what would have caused it though. I'm assuming that it must have just worn there over time. Perhaps bad heat treat in that area or some such?

[135sohc]

concentrated wear, heat treating failure ect. A co-worker had the NV3500 in his truck fail last month and I looked inside it and saw they run the countershaft/cluster gear on straight roller bearings with no inner race, surface was torn up just like they get on our stuff.

Simon/turbovanman2 offered a service to get the shaft turned down and a hardened race pressed on. not sure if he is still doing it or not.

[bfarroo]

I'll have to look over the bearing again and see, but I gave it a good once over and don't see anything out of the ordinary and can't seen any damage. I put the trans back together loosely just to keep all of the parts together. I'm going to pull one of the spares out of the shed this weekend and have a look at it.

[Reaper1]

There are a number of people that have run into this problem in recent years (myself included). I have no proof, but my personal thinking is that the heat treated surface developed micro-cracks over time, and then it started to flake off. Almost exactly like what happens to TIII cams. I'm going to send mine to Simon if he still can have the service done.

Now...back to trying to find a replacement bearing....anybody make any headway on this? The thread that was covering this hasn't updated in quite a while...

[black86glhs]

The case I had been working with cracked right there at the lubricating groove. So I gave it a rest. I still like the Honda bearing but the shaft needs to be turned to fit it. Maybe one day I'll get back to it.

[Reaper1]

Can you take a picture? I'd like to see what it looks like if you don't mind.

[black86glhs]

I don't have the case anymore. It wasn't a good one, had an ear busted off iirc. I was trying to see if it was relatively easy or a pain. When it cracked I scrapped it.

[Cliff Ramsdell]

The cause is normal wear and tear. I have scrapped hundreds over the years doing rebuilds.

I have about 12 '89 555 intermediate shafts left. They all have a perfect bearing surface. Drop me an email to Mopartek@aol.com and include a picture of the complete gear set.

Thanks,
Cliff Ramsdell