Help with leak

[ryder311]

Hello, I recently bought a 2018 PPV Tahoe with 100,000 miles on it.
Going through the DOD delete - while removing the exhaust manifold bolts I noticed a leak in the transmission engine seal.
Is that hole by the oil filter normal?
How do I fix the leak?

 

[CrashTestDummy]

Not 100% certain on the 1080 engines, but earlier versions of the LS-based engine has the oil pressure switch on the top back side of the block just inboard of the driver's side head. I'd check there to make certain the leak isn't coming from that switch. Otherwise, you're probably going to have to separate the engine and transmission to get to the offending seal, whether or not it's the rear main or 'barbell' cap on the engine, or the front pump seal on the transmission.

Biggest deal is separating the two bits.