Finally got the time to sit down and do the break in on the set, and I noticed the front 2021 unit was making what sounded like a grinding noise of sorts at higher speed steps. I put it on the test rollers, the grinding noise disappeared, and noticed that only the front motor on the engine seems to work correctly, the rear wheels didn't start spinning until speed step 40+, and even then they were spinning slowly. At low speeds it looks like it was making an effort to but failing to spin (stuttering). I'm assuming that noise was it basically the motor being forced to spin against some sort of binding, or the front motor making up the hauling difference dragging a deadlocked rear set of axles. Rear 2024 unit operating as expected
Before I open this up, is it a potentially simple fix with a loose wire somewhere? Or a catastrophic rear motor failure of some sort that should I shoot this over to Lionel and let them deal with their QC mess?
If need be I can grab a short video of the test roller run if it helps in diagnostics