NOT HOUSE (DRIVEWAY) BROKEN

I have a 2012 Chevrolet Silverado four-wheeldrive 6.6L turbo diesel with 156,000 miles on the odometer. Just within the past few days I have noticed a small leak, just a few drops on the driveway, below where the transmission meets the engine. I’m hoping it’s not the rear main seal. The dealership wants almost $1,000 to replace that rear main seal. I have read some remarks on the web saying that the leak could be from somewhere else. I don’t want to spend that much money and then not solve the problem. Brent Fulmer Via Email An important first step would be to identify what the fluid is—fuel (clear), ATF (pink), motor oil (amber), or engine coolant (pink/orange). If it's motor oil, begin at the top of the engine, looking at the turbocharger and other areas of the engine for either an oil leak or a fuel leak. On the lower half of the engine, look for an oil leak somewhere farther forward on the engine that could be run toward the rear till dripping off near the bellhousing area. The rear main seal on these engines haven't been a problem as far as we are aware The front seal on the Allison has been for some. So, it's important to

positively determine whether the leak is motor oil or ATF before deciding what to do about it. There is an aluminum transmission adapter that is sandwiched between the engine and the transmission. Engine coolant runs across the back of the engine through this aluminum adapter. A faulty gasket could allow coolant to leak. I have seen this once before. Let us know what develops.