[GenerationX]

Hi all, 2011 328xi auto 108k
This weekend I decided I wanted to do a trans flush. since the tranny is misbehaving. I researched the issues on my GM transmission and new fluid and filter will resolve the issues. While I was under the car removing the plastics, I saw oil on the plastic and skid plate. I can see oil on the pan, but it seems there's more oil by the axle seam. This site, https://germanformula.com/e90-bmw-32...t-leak-repair/ explains my issue to the T, but I'm not sure if the oil is coming from the VCG or OPG. I looked at the VCG and all three sides of the VC looks clean and dry, but I can't see the rear of the VC and I can't even get my hand back there to feel for wetness. I can't even see the rear of the VC from below because the diff is in the way. I'm hoping someone can help me find the source or at least guide me on where to look. I can't tell where the oil is coming from. I looked at the OPG and it's clean, but wet. But that can be from the wind splashing onto the OPG section.

[Mister_R]

Clean everything off that you can with brake cleaner, get some UV Dye and a black light, drive it a bit and check for source with the black light.

[GenerationX]

Originally Posted by Mister_R

Clean everything off that you can with brake cleaner, get some UV Dye and a black light, drive it a bit and check for source with the black light.

Do I pour UV die in the oil? What's interesting is, I threw a half quart of ATF in the engine to clean it up a bit before changing the oil. Obviously, the old oil will come out with a red tint, but I don't see that oil on the engine. I assume if I have a leak, I would have seen the red tint oil on the engine and I didn't. When I pulled off the shields and skid plate I didn't see fresh oil. I saw old dirty gunked up oil. I cleaned up the bottom of the engine, drove the car around the block, put the car back on the ramps and saw the bottom slightly wet. I don't smell burning oil, the manifold looks clean and dry, so I'm wondering if it's the oil pan gasket that's leaking. I saw several videos on replacing the OPG and that's something I will not even attempt.