P0707/p0708

I have a 99 Merc Sable LS, 24V 3.0 dohc engine O/D LIGHT FLASHING and Check engine light on. I have 4 codes 1ST) P0707, 2ND) P0708 3) P0135 4) P1131. JUST FYI. Just bought car today @ dealer auction as is. It appears to have a new 02 sensor. I'm not very good with transmissions assuming I need to check connections and pins @ Transmission Range sensor. Which also looks new.:confused:
I could use any experience, anyone can share!