DEF Solution On The Go Thunder Creek Equipment fill the bill with the new DEF tank. Published on: Mar 2, 2011 Tweet Post to Your Wall. Email Story RSS Permalink Print With new Tier 4 engines coming to market that require diesel exhaust fluid, having extra on hand is going to be more important. The folks at Thunder Creek Equipment fill the bill with the new DEF tank addition to their line. The top-of-the-line model can be outfitted with the DEF tank ahead of the main tank - as shown. Or it can be added to the top of the trailer tank. The system includes a pump for moving fluid from tank to tractor or combine. The DEF tank is a $3,675 option. For more information, call (866) 535-7667 or visit www.thundercreekequipment.com. The new DEF tank from Thunder Creek Equipment.