A Cummins engineer posting valid info about a Dodge transmission? I think not. If said person did it was a personal opinion about the potential NOT an absolute. Cummins engineers won't be cornered about the engine let alone a 3rd part drive train piece.
Excessive wear of the thrust washer COULD eventually cause transmission failure, after approxiately 100,000 to 1,000,000 miles. Choose a number.
EVERY single discussion around the potentetial failure of this washer was done without any data to back it up. The discussions were all theoretical about what COULD happen. The ones that were'nt were pure speculation.
IIRC, the late 04's included the updated washer, but, the only way to know for sure is check. When I rebuilt my 05 trans it had the new part. Dodge did not bail on EB's literally until the 06 models were released. The only reason they did so was because they could not retro the 06 controller logic to the earlier ECU's and gurantee the TC and EB would play nice together.