New to the diesel engines and trucks. Beforehand, thank you everyone who reads and comments. Truck starts and runs well. However, when trying to keep low rpms between 1st and 2nd gears down my drive I have a intense vibration or rattle. Accelerate or press clutch and sound is gone. 1st and 2nd sometimes rev the engine to what I think is too high (no rpm gauge) slide into 3rd and hello insane vibration/rattle. I'm clueless. Any ideas are appreciated.