What happened to my Gearbox?

Question

So, I am playing Better Than Wolves mod for Minecraft and I have a very nicely redstoned up kiln/crucible with a pottery wheel to the side. And it all works great most of the time.. But one to two times during a lengthy play session a gearbox just goes missing. I do not use the pottery table often enough to have ever seen if the box is dropping/on fire/busted. Just when I go to turn the system on, it is gone. Here is a picture. The box would attach the two axles and sits over the redstone repeater:

And if you watch this video at the time frame selected below you will get a quick little tour of the general wiring and such around it (its lighting a 3x3 hibachi).

https://www.youtube.com/watch?v=aAaKIS3GFxw&feature=player_detailpage#t=1867s

And then a little bit down the road (40:15 or so) you can see where I put in all the mechanical bits that will result in the connection in the screen shot above.

I am at a loss, the best I can come up with is that for some reason the repeater knocks off the axle but I have checked with the guy in the video over and over flipping switches in random orders to see what might cause it with so far not being able to reproduce it on command.

Answer 1

... It was catching on fire. On the right you can see the edge of a hibachi. The block above the gap between the two dirt blocks is then a valid ignition location which would be touching the axle. This would cause the gearbox, which is flammable, to catch fire.

So mystery solved, took quite a bit of testing and fighting with fire. Why can it go through solid blocks anyways :/

Anywho, thanks all whom helped me track this down!