Cluster Gear

My buddy is rebuilding my 18 spline transmission and found this inside the 1st gear cluster gear. Inside the bore it's starting to flakey/scale. What would cause this?

"Metal spalling is a process of metallic surface failure in which the metal is broken down into small flakes (spalls) from a larger solid body. This process occurs for many reasons, such as when another material impacts it at a high speed resulting in chipping the material, or due to corrosion, weathering, cavitation or excessive rolling pressure."

Can you please put that in layman's language? Are you saying normal wear and tear since I used to race and bang the gears?

It's broke

It's worn out
Not unusual if it was ran low on lube or had sit a long time
I've seen that on the tip of a output shaft, I ended up having a old time aircraft machinest weld it up with stelite rod and turn it back down to size and ran it
Not sure if that is the solution for that gear or not, probably not

A flake of metal debris in those rollers would have made quick work of that.

I think if it was mine I would call Brewers and ask if anyone has a sleave to repair that.

Already did. No. Brewers and Passon Perf doesn't have any. I'm looking for a new one and nobody has any.

Try Brian at SK speed in Lindenhurst, NY. You might be very surprised.

How did the roller bearings look at that position. I bet you could pick them out of the pile that fell out of the cluster gear. That’s the low gear end of the shaft. Must have been lots of pressure applied there.

You may have to go to a precision machine shop in your area to look at it. I wonder if you could take a cut out in the bearing to remove the damage and go with slightly larger rolling elements. I'd worry about a sleeve on the inside as it may weaken the tube some. Though looking at the pictures, there is a lot of meat there. So a sleeve properly installed could work. But I think that repair is beyond most automotive restoration and machine shops. I think you are into high end industrial repair shops. Hopefully the cost doesn't outweigh the replacement.

Here's a thought ... install a bronze bushing in there (just that one location - not the whole cluster) and run thinner lube in the trans.

Will call. Thanks. No dice on SK speed. Brian is a lot of knowledge. He said to put it back together until I find one. There were no problems except for a little popping out of first gear. That's not related to the cluster gear.

Well, it was worth a shot. I got a bunch of Nos 833 stuff from him over the years and his collection was staggering. The popping out of gear is most likely angle worn dog teeth on the gear, as he probably told you. Did you ask if he had an nos 1 st gear?

No way in the world would I even think of putting needle bearings in the cluster gear against a bronze bushing, no way
I don't know what exactly the heat treat is on those gears and the other gears in the NP833 but I'll bet they are really hard, same thing on the needles bearings and roller bearings
I would look into seeing if there is a material good enough to make a repair insert( that would have to be press in with the proper interference fit to keep it from spinning when hot) in it though
OP, your pursuing the best bet,, a new NOS gear
What does the cluster gear shaft look like on that end?

I think a bronze bushing is the most practical solution, not needle bearings on the bronze bushing but a bushing directly on the shaft. The gears are case hardened so boring the gear would involve grinding rather than boring with a tool bit.

WHERE did I say anything about needle bearings ?!?!? Install a bronze bushing in that one location INSTEAD OF needle bearings - it saves the cluster at least !!

The gear shaft does not too bad. Just some wear. I ordered a new shaft anyway. The tranny has a new 1st, 2nd, and 3rd gear in it already from my last rebuilt 15 years ago. They look excellent. He said the popping/sliding out of 1st is probably something else. I also have a new 1-2 hub assembly. It's going to be put back together with the new shaft and 1-2 hub assembly and wait until I find a cluster gear.

So here is the bigger picture... The world is out of 18 spline clusters?

Is Liberty Gear still in business? They maybe able to fix the cluster. Just a thought. http://libertysgears.com/

I will have more in stock at some point. Samples are approved, but it's a slow process.

Are you making them? What is your timeline?

Yes. No ETA right now.

Cool.


Let's put it this way, I called 18 Mopar parts suppliers and they didn't have any. I also talked to a heavy hitter Super Stock racer and he had 10 NOS but were all spoken for.

looks like a trans I disassembled with ATF in it Just not enough lube for that position in the transmission IMHO there is a lot of load on that part of the cluster.

Gus

Hmm... Mother Mopar did recommend ATF in colder climates for the 833.
Maybe not on a heavily loaded 18-spline trans though?

I've always ran straight ATF in all of my 833, street or drag racing only

I've been using Passon Perf trans fluid for the last 7 years. It's his special concoction. It's red and like ATF fluid. I switched to Sta-lube GL4 Gear lube about 6months ago.

Looks like I found an NOS cluster gear with its original cosmoline grease in its original cylinder that was sitting on a shelf collecting dust. Got lucky on finding it and the price.

Wow!!!!
Nice find!!!

Just my $0.02...