I removed the entire drive/motor assembly from the machine. It probably isn't necessary but it's a pain cutting off the old push-on nut. Everything is well laid out in the video although they make the push ring parts look easy. To install it I used a vice grip to hold the pin and a crescent wrench to push the nut down the pin. Make sure the nut is facing the correct direction and push really hard.
Fixing this without pulling out the dishwasher would be a huge pain but might be possible. Even if your machine is hardwired to electric it can still be DIY. Make sure to take your time disconnecting and reconnecting all water lines. I had a leak where the drive assembly attaches to the bottom of the tub. I was barely able to tighten it in place - make sure those clamp rings are snug or at least accessibly before testing.
The gasket itself took about 10 minutes to put on. The disassembly and troubleshooting probably took 2+ hours. Most of that time spent tracing the leak while trying to force the dishwasher through all the cycles. I'll say 45-60 minutes from opening the bag to testing the dishwasher. From memory, I used 5/16 and 1/4 inch socket, and a Phillips screwdriver. Plus an adjustable wrench to remove the supply line.
The video here helped tremendously and I'm more than happy to support a company that provides this service.