The Norge washers that the Atlantis was based off of tended to be pretty noisy under normal operation, and the Atlantis machines shared that same trait. As such, it can be a bit difficult to determine what sounds are normal and what aren’t. On my machine, it always had a bit of a metallic clunk when it would switch direction on the agitation stroke, as well as an audible groan from the gears, similar to that of the Norge washers. However, before I fixed it, it also had a thumping sound that came and went that sounded like the gears weren’t meshing up just right during agitation. I believe this was due to the broken locking tabs just hanging out inside the transmission. It also had a strange whirring sound during the spin cycle resulting from the transmission not locking up. These both went away and never resurfaced with the new gear. Unfortunately, rebuild kits don’t exist for these transmissions. They were originally meant to be a throw-away item when they failed. As such, there was also no OEM gear available. They are still fixable, however. The transmissions can still be opened, as the top is crimped into position with metal tabs. The gear is available on Amazon through a company called MTC (Part # 20234). The center gear can fail in a variety of ways. I watched a YouTube video where one had stripped out teeth. On mine, however, the tabs on the side that lock the transmission up for the spin cycle had broken off, causing the machine to only be able to spin very slowly, and agitate at the same time. If you decide to replace your center gear, I would also bank on replacing the tub seal kit at the same time, as it will be next to impossible to remove without destroying. For the 2003 model I had, the part number was W10219156. Note that this P/N is only good for models equipped with the high torque transmission.
Hope this helps,
Thatwasherguy.