4T65E Deep Creaking in Reverse only

My transmission started a deep creaking sound only in reverse after getting done with the major mods (had engine cradle out, new xp cam, headers, intercooler etc)

Now in reverse only it Growls, almost like there is way to much torque. It reminds me of being in gear stopped with the throttle at 2,000 RPM & then gradually removing the break so you creep forward a few inches. it makes a deep creaking sound. My car does this now all the time in reverse only. it does it with my foot completely on the break, or just letting the car go backwards in reverse with no break on.

you can here a minute of it here:
http://www.youtube.com/watch?v=x0chb...ature=youtu.be