I have a 2007 yulon denali and its past the 3 years on the 3-36 warranty. I know the drive train is 5 years - 100,000 miles but what about all the other things.

I want to purchase an aftermarket warranty but have no idea who to get it from. The dealers now outsource the warranty's to other companies. How do I know where to and if I am getting a true GM bumper to bumper warranty?

Are there any other 3rd party companies you here have used with no problems????