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Silverado HD SB -- 38 gal. Aux. Fuel Tank -

n75v111n75v111 Posts: 243
edited March 2014 in Chevrolet
Tank - Mounted in place of spare tire.
Fab. drawing available for the asking-
Fabricated Steel (12 gage/.112" thk- about 75 lbs.
31" wide at rear w/sides tapered in to 24" at front to clear exhaust pipe outlet and shock. 31" front to rear. Front 12" deep behind axel. & Rear 9" deep at bumper/hitch.

Bolted to upper spare tire frame w/ four Reese 1/2 self locking bolts. Filler neck at rect. hole behind license plate.
Cost $250 to have made locally-

Purolator PRO#12S 35gph electric transfer pump-
Operated by Aux. Switch that comes w/with Snow Plow Option. Cost $33.00

Fuel is transfered to main tank by adding 3/8 hole in upper metal filler neck and installing a modified 1/8 NPT brass tube fitting connected to 90 degree 1/8 NPT brass elbow connected to 5/16 brass barb connected to rubber fuel line tubing.

This has been somewhat of a do it your self research and design project to find all the wireing for the Aux Switch and figuring out the double wall filler neck system.



  • mledtjemledtje Posts: 1,123
    So, does that let you do 1000 miles without stopping?

    And, where did your spare?

    Mike L
  • obyoneobyone Posts: 8,054
    gas weigh?
  • n75v111n75v111 Posts: 243
    Spare goes in bed when towing 5th wh. otherwise don't carry it unles going out of town etc.
    (have never needed a spare when tires are new)

    Gas Milage??
    Have not had unit on long hiway trip.
    Best I get 10.0 mpg B&F to work.
    64 x 10.0 = 1000m -- I wish--but i got it for the power so not complaining.

    Love this truck -- Just wish GM had more brains on proper fuel tank requirements.

    Gas weighs 6 lbs/Gal last time i figured W&B on the airplane -- What's your point??

  • obyoneobyone Posts: 8,054
    is sacrificed for gas.
  • n75v111n75v111 Posts: 243
  • rayt2rayt2 Posts: 1,208
    When I ordered the truck, would have gotten the 34 gal opt. but with the shortbed you get what you get so at 200 miles or so when towing my trailer I am looking for the next gas station, and life goes on......
  • akjbmwakjbmw Posts: 231
    Pullin' a trailer or not, restroom visits come about as often as fuel. The extra distance is to get to the next cheaper gas area. Ever notice how the "lonely" stations charge so much more?
  • rdve80rdve80 Posts: 139
    I added a 41gal aux. tank with upper tool box to my 1/2ton Silverado SB for a total of 65gal. Never run solo long enough to use it all, but should be over 1000 miles. This aluminum tank/tool box is about $450 from Northern. While I went with a duplicate fuel pump setup ($$), if you used a fuel transfer method, cost would still be reasonable. The in-bed location puts this weight between the axles rather than totally behind the rear axle.
  • n75v111n75v111 Posts: 243
    Pulling 10,000 lb 5th wheel.

    Sure beats looking for gas stations when your down to that half tank level with the 26gal tank on the SB's every 100 miles or so. (:-)

  • I believe the cab chassis models have an aux tank mounted in the same place. They show it in the Silverado brochure.

  • volkejvolkej Posts: 108
    75v - The location of your aux tank seems a little risky. What kind of protection do you have in case of a rear end collision? And what does the addition of the tank do to your warranty? Considering the past problems that GM has had with fuel tanks and trucks, I would think they would frown on anything that would make these trucks susceptible to fuel tank fires.

  • n75v111n75v111 Posts: 243
    Well, Tank mounted between the frame rails even to the rear may be better than those that mount them in the Box behind the Cab.

    GM Warranty -- This arrangement simply transferrs the fuel to the main tank and does not alter the main fuel system. However warranty issues kinda depend on the situation. I have had two gm dealers send people to see this installation and copy it for what that's worth!!

    If your worried about SAFTY and WARRANTY issues it would be best not to do anything I guess, but I don't like looking for gas stations that i can get into with long 5th wheel every 100 miles.

    As for the GM made aux tank for chassis cab they still used the old frames - NOT the HD frame - and thus would not fit. Course this is mounted exactly in the same place as GM mounts it you might note.

This discussion has been closed.