Hi all, I recently pulled my differential from my '20 490 since I had some sideways movement (~1/16" each direction) when I pushed and pulled on the wheels when it was up on stands. I suspected the thrust washer was shot - and was right when I got it apart - see picture (3 pieces). The new bronze one from a Model T supplier fits perfectly. I added additional .030" shims (also from Model T supplier) to close up the remaining gap in lateral movement. Also, while the car is a '20, I cannot definitively say the rear axle is the original. The ring and pinion are bevel cut in mine. As I understand, the bevel cut wasn't introduced until '22 in original assemblies, but there were replacements of the straight cut with bevel cut available as service items. Anyway, the question I have is the stamped numbers found on the mounting surface on the axle housings where the torque tube mounts. In this case, its stamped with a 576 on both halves of the axle housings. You'd never see these unless you pull the torque tube off. Does anyone know what these numbers mean?