4x4 - 5.0 ltr STANDARD XL ......... I have a squealing/whirring sound when decelerating to shift or slow down. As well, I am getting frustrated as the only way my truck wants to reverse the first time is in 4 low. It has no isues going into any other gear! What could be going wrong? I was told to check the transmission fluid, I did that and it is full.