On the Duramax, the primary probe can be installed on the passenger side exhaust manifold. On a Dodge, the probe can go in the middle of the manifold where it collects and dumps into the turbine housing (just don't drill dead-center—there's a divider wall where the two sides of the manifold collect). On Fords, you'll need to crawl under the truck and drill into the bottom of the driver's side exhaust, depending on the engine.