I installed a MRC 1634 sound decoder into a Athearn SD40. This is basically the same install as I did with a Tsunami and a RTR AC4400. The step by step is very similar to this thread Tsunami and a RTR AC4400
The difference is that I removed the rear weight and screwed a piece of sheet metal in it's place. This provides a place to mount a mini oval speaker facing up. This shell has the see through top fans that are perfect for letting the sound out.
Here is a video of the SD40 running on YouTube.
The difference is that I removed the rear weight and screwed a piece of sheet metal in it's place. This provides a place to mount a mini oval speaker facing up. This shell has the see through top fans that are perfect for letting the sound out.
Here is a video of the SD40 running on YouTube.