damage on countershaft
 

This is my ats 4.9 final drive, is this relegated to nothing more than just a nice paper weight now?

Re: damage on countershaft
 

Looks like they are ready to sheer off soon. Yup, fine looking paper weight you have there.

Re: damage on countershaft
 

pitting on the face of the tooth like that is a sign of a few things
1. overpowering the gear or lack of lubrication
2. improper gear mesh from tooth profile design
3. gear hardness is not correct and caused this

there is a very fine line line in the way that a gear should be hardened get them to hard and they are brittle if there not hardened enough they will pit and wear like this one i would have some one do a rock well test on it and question ATS about it. What i do find odd is usually when there is a issue with wear like that it also shows on the bearing surface there will be lines on it where the rollers of the bearing have dug into it under power.

Re: damage on countershaft
 

I have some pits like that in my liberty second gear on the main shaft. Mine arent nearly as bad and they've been there for a few years now. Whenever it blows is whenever it blows.

Re: damage on countershaft
 

Nothing more needs said. No way to repair it, so either you run it until it fails or replace. It will either get worse or stay about the same. Given that it doesn't seem to be corrective pitting, it will likely continue to get worse.

Re: damage on countershaft
 

I'd like to add that the trans might not have been set up properly. Looks like most of the wear is on the lower 2/3rd's.

Re: damage on countershaft
 

How else should it be "set up"? The shaft center distances are fixed distance. Not like it's adjustable like a rear ring and pinion. This issue could be anything from poor fluid film protection, excessive torque for the surface hardness, improper gear hardening, or improper gear design/manufacturing.

With the pits being on the dedendum of the tooth profile, it could also be hydraulic pressure from fluid being trapped in microcracks of the gear which resulted in gear pits only on the dedendum rather than the pitch line.

We'd have to know what fluid was used as well as what torque the engine was making to help out much further.

Re: damage on countershaft
 

You can shim anything you want in a gear set. If it's not setup properly it can happen.

Re: damage on countershaft
 

I know you can space anything around, but the ring gear is shorter in height than the countershaft gear, which means the restriction on the full contact is with the ring gear. The full portion of the ring gear is being used in this case given the size of the non-contact area (it's size looks exactly as I'd expect) - this top portion is also where the factory install heights normally end up. As long as the ring gear (shorter gear) is being fully utilized (which it seems to be) it doesn't matter where it's contacting the countershaft (taller gear) on a fixed distance transmission.