If your engine oil is not that dark and it's not coming from a manual transmission or transfer case... I don't know the layout or options on a Montana...
I'd guess there's a hydraulic engine mount and the oil inside the rubber mount is leaking out after 19 years or use (assuming it has not been replaced).
I know my 2003 leSabre 3800 engine had a hydraulic mount on the front of the engine to smooth the vibrations from the pistons when the engine was torquing against the mount.
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Answers
I'd guess there's a hydraulic engine mount and the oil inside the rubber mount is leaking out after 19 years or use (assuming it has not been replaced).
I know my 2003 leSabre 3800 engine had a hydraulic mount on the front of the engine to smooth the vibrations from the pistons when the engine was torquing against the mount.
2014 Malibu 2LT, 2015 Cruze 2LT,