The only easily done maintenances for a manual or automatic transmission is the Transmission Fluid change. While Chevy says that this should be done every 100,000 miles, I did mine at 50,000 with royal purple and the transmission has been fantastic since then. I am currently at 85,000 with an original clutch and transmission.
It is bolted in the valve body that is inside of the transmission.
With a 07 chevy cobalt key
in the trunk
It does not have one.
No it will not
87 octane
.040
to the low side
see your Chevy parts man.
16x6
yes
13.3