2002-2009 Cummins 5.9L/6.7L 3rd Gen Recirculation Door (DT-3962-Y)

The Doors

Blend Door USA manufactures all of their products from solid pieces of aluminum. There are no welds or rivets in any of the products.  Everything is CNC machined to maintain the highest quality possible and to ensure a perfect fit every time.

The drivers are key-cut so they will solidly engage the doors and will never fail. In the few instances where a key-cut driver won't work, the drivers are drilled with an off-set bore and are held in place with a cap screw.  This allows the drivers to stay engaged with the door when there is not an actuator holding it in place, like the 3rd gen Ram dual zone blend door drivers. All splines are broach cut into the drivers to ensure perfect engagement with the electronic actuators. 

So why do they use aluminum instead of steel? Aluminum is much lighter than steel, and it will never rust. Since the aluminum is lighter, they are able to make the doors significantly thicker and still maintain the same weight.  This allows the doors to be much stronger than any steel replacement ever could be. Aluminum can be machined in a solid piece, which is why the doors do not have any welds or rivets holding them together.  Steel doors are tack welded together, which creates a weak spot and potential failure. For an HVAC system, aluminum is superior in every way. The doors are the strongest in the market, period.

Foam Seal

Blend Door USA uses open cell foam to seal the doors.  Most factory open cell foam is a polyester based foam that is biodegradable, which is why it comes apart and blows out of the vents. Their foam is a synthetic polyether based foam that is not biodegradable and therefore will not deteriorate like the original foam. A common question that they get is “Why don’t you use closed cell foam like the other guys?” The simple answer is, they'd love to, but they have yet to find closed cell foam that will perform satisfactorily in an HVAC box. There are a few requirements that foam must meet in order to be acceptable for use on the replacement doors:

• The durometer or “squishiness” of the foam must be soft enough to sufficiently seal the box. The plastic housings have a very loose tolerance for what can be considered “flat.” We’ve had boxes here that have had as much as 1/4 inch gap on the sealing surface when the door was closed.  The foam must be able to compress completely on the high side in order fully seal on the low side. Most closed cell foams are too hard to seal properly.
• The foam must be durable enough to withstand the extreme heat and extreme cold that an automobile will experience. The air conditioner evaporator will produce air temperature around 40 degrees F and the heater will produce around 200 degrees F. Don’t forget the interior temp when the car sits outside in the summer sun all day in Arizona or all night in a North Dakota winter. Very few types of foam can withstand this kind of abuse.
• The foam must be American made.  We pride ourselves with an American made product produced by American workers.  We will not lower our standards by using a cheaper foreign made foam to increase our profit.

This door will fit 2002, 2003, 2004, 2005, 2006, 2007, and 2008 Dodge Ram 1500 trucks. It will also fit 2003, 2004, 2005, 2006, 2007, 2008, and 2009 Dodge Ram 2500, 3500, 4500, and 5500 trucks as well as the 2007, 2008, and 2009 Sterling Bullet trucks.