Jack cylinder leaking???

[CADman_KS]

We have a 2020 Chevy 3500HD with a Dmax. This is the first truck that I have owned that had DEF, but have had other vehicles that took DEF, so I'm famaliar with that.

I noticed the last time that we took our 5er out that our left front jack has a fine layer of oil film on it. At first, I assumed that we had a fitting leaking. I checked all of those, and they were tight.

Then, after traveling, I noticed that we have a light film of grease on the underside of the front of the 5er. Now, I'm wondering if the truck is putting out that much soot, and it's getting on the front, or something else is going on?

Anyone experienced this with a new truck, or is just that jack cylinder leaking, and getting on everything?

PS: We have a removable mudflap that is on there all the time when we're pulling, and it has a heat shield on it, if that makes a difference...