i'm a manual guy in everything...
but from stuff i've read: i understand you can use the 2006 4L60E and swap in a 07+ input-shaft/drum with I.S.S reluctor, and add the I.S.S sensor plus 07-08 trans internal harness. i've read some 2006 4L60Es had the location for the I.S.S in the pump, others did not. if yours does not have it, you will also need a 07+ pump body.