Maytag washer does not spin

Unit developed leak and we replaced the air gap assembly and solved that problem. After reassembly, unit will fill, agitate and drain, but does not spin and has the burning belt scenario. I have tried reassembly several times looking for a mistake. I removed the barrel cover and agitator to look for a jam. I have checked the lid and check switch.?? Would you tell me the purpose of the check switch, and would you give me an idea of what I might try next to solve the no spin problem?
Thanks,
Max

Never mind. I have found the problem where the drive attaches to the barrel. It’s like a train wreck. Am going to slide a new washer in under it. Still, thanks for the service you provide here.