I'm a little stumped here. I have a 2010 5.3L Silverado 6 speed Auto with about 49K on it. Over the past year or so, I've noticed that the truck seems to downshift really rough when decelerating. For example, you drive up to an intersection, the light turns red, you let off the gas and the truck will "Jerk" as it downshifts into a lower gear. I've also noticed this to happen anytime you pull you foot off the gas and break fast because somebody pulls out in front of you wanting to get slammed. Other times, I will be cruising along in a flat open parking lot, let off the gas and experience the hard downshifts. This also happens when you are in trailering mode as well. No SES/CEL, or other problems except for the picture attached. This was noticed around last summer when I was changing the oil. It seem that some type of something is leaking around where the transmission meets the gear box (or something like that). I wipe it off every time I change the oil (along with the front sway bar), but it always seems to return. It's never enough to drip on the floor in the garage, but anything leaking on a 2 year old truck is just no good. Thoughts? Thanks!