Transmission Cooler Assembly Leaking?

Anyone know how hard it is to replace the O-rings on my transmission cooler assembly (part #33490-34010) on my 2011 tundra? It is leaking like a m****er and I’ve heard from someone that I have to drop the transmission to get to it?
This is the part:

 

Bump

 

That's not the cooler unless you have a 19-21. Regardless, the o-rings for it are the same as the actual cooler that bolts in place behind it. It's 3 bolts and you'll likely want to be prepared to do a drain and fill (or fill and fluid level check at the very least).

You can look at the Genuine Cooling Systems install instructions for the process.

 

Just watched the install video. Doesn't look too difficult. Thanks for pointing me in the right direction!