I’ve noticed when deceleration and foot off gas at about 40/50mpg transmission sounds like its making a groaning noise. I though it was brakes but I don’t think it is, it mostly happens at slower speeds.
The other thing is that when reversing my rear camera used to stay on the whole time, now it goes on and just turns itself off for some reason after a few seconds half way though reversing - what am I missing?!
Maybe a dumb question, as I don’t know how familiar you are with these cars, but are you sure it’s the transmission and not the exhaust? During deceleration in certain gears at certain RPMs, my exhaust “groans” quite a bit.
You mention “squealing” in the thread title, but didn’t talk about it in your post - what’s squealing?
I haven’t experienced that exact symptom with the reverse camera, however sometimes (maybe 1 in 50 times) my camera doesn’t come on at all while reversing. Seems like a software glitch in my case - something like if I put the car in reverse while the MMI software is still “booting” then it doesn’t catch the ECU’s signal that the car went into reverse.
A good way to test to see if its the exhaust is try putting the car in N right when you start to hear the noise. If taking the load off the motor and the transmission stops the noise then that could start to point you further in the right direction.