Wow, you guys are incredible. I should do some abstract stuff.
Yes, I know the right rear wheel is messed up (didn't see it til after I scanned, durnit). Also, at first glance, the perspective of the whole truck might seem off, but that's because it's a rock crawler, and therefore it possesses the ability of extreme articulation. And yes I know my shadow suck, need to work on that a bit... :/
I really like this drawing from you. You got a nice angle and the style is easy to appreciate. However you're very fond of using solid lines and outright attempting to hard sketch a lot of the details. Let me show you an example.

The above hand is done with an
almost continuous line, from point A to point B.
The second hand has been done with multiple strokes and crudely drawn shapes. Thats why it looks slightly fuzzier and a little mechanical for the time being. But the advantage is that you put in the detail more vividly this way and you can erase the excess lines later eliminating the rough look. In the end the second hand is going to look different and generally more appealing. (depending if that is in fact where your taste is). I'm not saying you don't do this already but it appears a lot of the major detail comes from a hard line method.
I'm not saying you should change the way you draw, I'm just opening up a possible path to take. You can keep going the way you are and drastically improve it.