GM rear fuel tank

[Ridin'GMC]

I'm trying to gather more information about the GM rear fuel tank found on the 3500's. I need more fuel capacity in my truck, recently looked into the titan tank and decided not to use it because of the fuel tank hanging low. I do take it off road once in a while and half the time I crawl over something, it is right near the frame. I don't want an in auxiliary tank because I use every bit of the bed space. I do not have a spare tire in that location.

Can the 3500 rear fuel tank work on my cab configuration? Is there a different filler neck location or is it filled by the same spot?

Any additional info would be appreciated. Titan rear mount is out of the question, $1700 for 30 gallon is a rip off when a direct tank replacement is cheaper. I prefer plastic constructed tank because of no corrosion.

 

[skintback]

I don't have any real good info for you but i do have a rear tank setup that came off a 03 cab n chassis dmax and the way it looks you will need the rails that go for side to side on the frame to make it work or make your own because the spare tire rack is diff than the way the rear tank bolts up i was thinking about putting it on mine and ditching the stock tank as for the fill neck it came off a flatbed so it had 2 filler necks and a lift pump would transfer the fuel out of the rear tank into the front one it looks like the tank is about 15-18gals not sure just a guess

 

[TheBac]

I had first wanted to use one of the CnC rear tanks in the half ton, but could never find info about them. (re: part numbers, how to install, etc)

 

[hondarider552]

Shoulda bought a long bed

 

[Ridin'GMC]

Shoulda bought a long bed

Long bed suck. It looks goofy to me.

 

[gamudslinger88]

I'm in the same boat. Titan tanks are a rip off and I also do wanna clutter my bed with more things. I thought about plumbing in a fuel cell into the factory tank with a small pump. Put it in the huge hole where the spare goes. Should be able to fit another 15-20 gallons back there. But when does the time and money invested pay off? That's my main concern. I been keeping an eye open for a used well priced titan but I'm putting a beans in my tank soon so it's a double edge sword. I'll just stop more often for now.

 

[Cougar281]

Long bed suck. It looks goofy to me.

That's a matter of opinion. To me, short beds look goofy . Plus short beds are not as useful. Can't fit a full sheet of plywood in them and close the tailgate.

 

[DIESELMAFIAPER.LB7]

The c&c tanks won't fit a cc/sb truck not enough room back there long bed could make it work but you would have to gut the bracing in between the frame in the back and lose the spare tire mounts ect. Titan I though had a new lower profile tank or a kit that mounted a small 15 gallon tank in the same area your thinking I'll have to go look

 

[Ridin'GMC]

I don't really care about losing the spare tire mount. I got rid of the spare tire years ago, I'll have to make a new spot for the spare tire eventually, 37" tires isn't going to fit in the stock location. Currently, the spare tire location is vacant, I would like to put some use in that area. Which is what I thought about the auxiliary fuel tank. I'll have to measure the dimension of that area. I thought about using a k5 blazer fuel tank. It's 28x28x13.5. Not sure if the frame is wide enough to fit.

 

[THEFERMANATOR]

That's a matter of opinion. To me, short beds look goofy . Plus short beds are not as useful. Can't fit a full sheet of plywood in them and close the tailgate.

I can fit a full sheet of plywood in mine, and I don't have any bed. Thats what I like about a SUBURBAN. I can fit a full 4X8 sheet of plywood in the back, and close the doors. Then I can empty it out, and fill it with 8 people.

 

[malibu795]

I have a C&C aux rear tank off an 08 LMM C&C 3500HD dually. its ~33gls you will need to remove the spare tire hanger brace/brakets and build your own. C&C are ~34" wide outside to outside, none C&C are ~48"
I was thinking about doing that with mine then just mounted the 60gl tank on the frame behind the cab.

 

[Ridin'GMC]

Is there any better pics of how the tank is mounted? Googled for hours and couldn't find anything good for me to see how it is set up. I need to keep the frame strong as possible for towing as well. Kinda bugs me out that I can't transfer the rear bracing from the CnC to mine. Unless it can be modified to extend or I'll have to make one from scratch that is similar to the CnC for the ease of install and frame strength.

 

[Ridin'GMC]

I have a C&C aux rear tank off an 08 LMM C&C 3500HD dually. its ~33gls you will need to remove the spare tire hanger brace/brakets and build your own. C&C are ~34" wide outside to outside, none C&C are ~48"
I was thinking about doing that with mine then just mounted the 60gl tank on the frame behind the cab.

Where were you able to find the fuel tank? It seems it is difficult to find the balance module, harness, tank, and the sender. I'm not sure if the harness are different from the CnC to ours, can they be plugged in or is it a complete different harness?

 

[malibu795]

harness is little different uses an 6.5 style fuel pump to transfer from aft to forward tank.. and a module to calculate combined capacity of both tanks and when to turn the transfer pump on and off... im sure they can be grafted together and the ECM/BCM and be told to read both.. I stumbled across on at the local junkyard. bought the tank, sending unit and straps for ~200.00.. like to buy the frame 4WD 159"wb off them but not at 2000.00 for the frame

found picture of a DEF C&C truck at a dealer