Which O2 sensor to buy??

[mptoledo]

I purchased an obd2 reader today and only read two codes.
1.)p1133= oxygen sensor, adaptation, lower load bank two above limit.
2.)p1126=o2 sensng range 1 cyl 4-6

I have read on hear that the o2 sensors should be replaced around this mileage. I would love to save $500ish if I don't have to spend it. I know nothing about 02 sensors, but was wondering if it is possible to clean them?

I just did a transmission fluid and filter swap. I was hoping it would take care of the churning noise/feeling I get when I start the car up and put it in drive/reverse. I noticed that probelm driving home from a 90 mile trip a week ago. It would shift up and down fine, both auto and tip. It was only when I stopped at a light it would make a chruning noise. That part is worrying me enough to not drive it, until I figure out what the heck is going on. As stated previously, everything else is fine.

Any Ideas on the tranny?