New Headunit, Audio Tearing + No Rear Sound

Hello everyone first post here, I was replacing the headunit in my Jaguar 2003 X-type no nav and purchased a sony unit. I had power problems with that unit because it had some crazy built in amp(hi-power) so I decided to go with a JVC KW-R940BTS.
I wired everything correctly and tried it out and when it reaches a mere 14 volume it starts distorting and tearing awfully.
I tested the fade out because my rears are factory and my fronts are Pioneer TS-A1670F 6.5" and what I found is the rears don't play any volume even when at full fade.
Also when the fronts are at full fade the distortion actually happens LATER at 25 volume, its super weird. Also another note is when I had my sony unit the rears worked fine and could get louder than where this is happening now.
JVC support didn't help at all and I am positive my wiring is correct. I even shook some of the wires while playing sound and couldn't find a loose connection. Please help there is no info anywhere!!!