Water in tranny fluid

[Flavert]

2004 GMC Yukon XL 1500 SLT 2wd 133,000 miles original owner. I was getting the TCC shudder so I drained the tranny fluid to start the repair. Fluid looks like Pepto Bismal. From my online research it appears I need to replace the radiator, rebuild the tranny and get a torque converter. My question is, what do I need to replace in the tranny? There are a lot of different rebuild kits out there with different amounts of parts. I just want to put the tranny back to stock.

Thanks,
Rick L.