We added a new class to our project that derived from the UWheeledVehicleMovementComponent class and used the 4W as a template for how to implement it. There were a few work-arounds but it works fairly well. I’m just now working on getting the tank to turn tighter as it makes fairly wide turns. nVidia has a SnippetVehicleTank.cpp file that will show you how to basic things. (Source: SnippetVehicleTank example)
Also, our artists had a heck of a time getting the models setup correctly for the tracked vehicles. Maybe once we get the code solid I may consider sending it to Epic for inclusion in the engine.