for the tranny on this one i used pencil led, rub it on with your finger, then black pastel dust and some rust color.
i also like to use black and some white pastel on the hoses black for dirt and white gives a faded look.
theres no dry brushing on this one. since the engine is black i rubbed a bit of pencil led around to highlight bolt heads and stuff. and a bit of light brown pastel for some dust on the manifold.