Hey, That's a Sexy Tractor

As many of you know, Chad is an engineer for John Deere.
And although he no longer works on tractors (he designs golf and turf mowers and utility vehicles now), he does still enjoy tractors.

He has created a John Deere 9000 series tractor -- out of Legos.
He only used Legos we have on hand.
No extra sets were purchased to create this.
That's because we already have a bajillion Legos.

Isaac helped a little by building the differential.
Did that sound good?  Like I know what I'm talking about?
Because, really, I don't.  OK, sort of.  I know it's at the back and has something to do with the transmission.
I do know that the engine is a straight six.
My old car used to have a slant six.