Aluminum Tank Industries rectangle aluminum auxiliary fuel tank is available in sizes that range from 51 gallons to 66 gallons.  These light weight aluminum fuel tanks offer a variety of sizes and shapes that easily fit in your bed space. 
ATI auxiliary tanks are used to increase driving range and fuel capacity by connecting directly into your factory fuel tank through the factory filler neck. 
All ATI auxiliary tanks come standard with a 3/8″npt outlet, vent with rollover protection, automotive style fuel cap, and fully welded baffles to reduce slosh and add strength.
These tanks are constructed from rugged diamond plate aluminum and are all available with a black or white powder coated finish. Custom tanks are available upon request. 
ATI FUEL SHOTZ (Available as Optional Accessory on Product Page)
These tanks are designed for use with the ATI Fuel Shotz diesel install kits. The diesel FUEL SHOTZ installation kit can be installed in less than an hour.  The unique system connects the auxiliary tank to the factory tank with the factory filler. 
This will keep your factory tank completely full until the auxiliary tank is empty. You will know your auxiliary tank is empty when your factory fuel gauge moves off the full mark. 
The FUEL SHOTZ system installs quickly and easily. No wires or switches to install.  The system has rollover protection on the tank and on the factory fill neck adaptor.  Detailed instructions are supplied with the FUEL SHOTZ installation kit. 
Rectangular Diesel Auxiliary Tank Sizes

AUX51R: 51 gallon * – 55″L x 9″W x 24″H

AUX58R: 58 gallon * – 51″L x 21″W x 13″H

AUX65R: 62 gallon * – 54″L x 21″W x 13″H

AUX66R: 66 gallon   – 55″L x 18″W x 17″H

See pictures of each tank below:
*51 gallon size has a 55 inch notched bottom length and 60″ top length.
*58 gallon size has a 51 inch notched bottom length and 58 inch top length.
*62 gallon size has a 54 inch notched bottom length and 60 inch top length.
AUX51R Slim Auxiliary Tank

AUX51R: 51 gallon* – 55″L x 9″W x 24″H / fits short beds
*51 inch notched bottom length and 60 inch top length
The AUX51R includes 4 mounting tabs; 2 on the front and 2 on the side.
AUX58R Auxiliary Tank

AUX58R: 58 gallon* – 51″L x 21″W x 13″H / mounting tab modification for short beds
If you have a short bed truck, you need to request a modification to move the side mounting tabs to the front and back so the notched tank length can fit between the wheel wells.
*Notched bottom length of 51 inches and top length of 58 inches.
AUX65R Auxiliary Tank

AUX65R: 62 gallon* – 54″L x 21″W x 13″H
*54 inch notched bottom length and 60 inch top length
AUX66R Auxiliary Tank

AUX66R: 66 gallon – 55″L x 18″W x 17″H
Note: mounting tabs add 1.5 inches on each side of the tanks listed above.
If you have a short bed truck you may need to add a modification to move the mounting tabs from the sides to the front & back so the tank can pass through the wheel well.  Please call or contact us if you have a short bed truck to confirm.
The fill neck adds 2.5 inches of height to the top of the tank and has a 2.5 inch diameter.  The fill neck is also located halfway between the center of the tank and the left edge of the tank.
For example, the TTR51 is 60 inches long.  The center of the tank is 30 inches.  The fill neck will be located at the midpoint of the left edge and the tank center, which would be 15 inches from the left edge of the tank.
All ATI diesel auxiliary tanks come standard with the following:

Meets DOT requirements for diesel auxiliary.

All aluminum fuel tank construction.
Quick easy installation.
Tanks are baffled to reduce movement of contents.
No wires or switches to install.
Rollover protection.
Automotive style fill cap.
Hold down brackets.
Pressure and leak detection test.
Clean and free of debris inside and outside of the tank.
1 year limited