Attention: TDR Forum Junkies 
Just thought I'd pass on my experience installing the Titan "SuperTank" 57 gallon replacement tank on my 05. I'm just an average backyard mechanic so if you see something you think can be done better, have at it... 
1. Get you OEM tank as close to empty as you can. This will make it a lot easier to handle, and get the hoses off while it is lowered half way. Jack up the rear of the truck, and put it on jack stands, for more room. Use the floor jack with a 4X4 block on it to hold the tank up while unbolting it. The bracket bolts, holding on the tank, can be a little tricky to get to and you will need a good "deep socket" to get them off.
2. I took the fill hose and vent hose off from the "fill neck" before lowering the tank. Releasing the feed and return lines can be a little awkward as you have to compress the inner catches, on the connectors, while "wiggling" them off. In fact, I ended up taking the "pickup" assembly out of the tank, while the tank was half way down, so I could get better access to the front connector. Be careful that you don't damage the pickup assembly or the float while taking it out.
3. The instructions say to bend the float arm down so that it lays flat with the bottom of the pickup assembly. I did not find this necessary, as the float was already in that position.
4. Put the outer strap mounts into their notches before you put the new tank in. There is very little space between the frame and the tank, after it is in position. Jack the new tank up, about halfway, to get it close enough to attach the fill and return lines (they just snap back on). I didn't have to modify the fill and return lines (lengthen or shorten) to get them to go back on.
3. After the hoses are connected, jack it into the final mount position. The bolts supplied with the tank, for the brackets, are "too long" (the unthreaded shanks aren't necessary) so I had to replace them with new bolts, with no unthreaded shank to them (threaded all the way to the head). Once again, getting the nuts onto the mount bolts is a little tricky (especially the front one) as there is very little space to work in.
4. You will have to cut your fill hose, and vent hose to fit the fill neck, as the tank sits higher. Also, I had a slight "crimp" in the fill hose as the fill neck on the new tank is longer then the stock neck, and is angled up at about a 45 degree angle. This puts a low point in the fill hose between the fill neck and the tank, but it was not a problem filling the tank full, after the install.
5. I put 10 gallons of diesel in the tank. That did not register much at all on the fuel gauge. Went to the station and put an additional 46. 25 gallons in for a total of 56. 12 gallons. You might get more in if the back of the bed was a little more level. but with the bed unloaded, it angles down toward the front.
6. The DTE computer will not work with this install. It goes up to about 480 "distance till empty" and stays there until the float starts to drop. Then it gives a "false" reading, as it is figuring this on a 35 gallon tank, not a 57 gallon one. This is a small concession for getting a bigger tank.
7. I have put about 470 miles on the vehicle since the install. The fuel gauge reads just about 1/2 full. Don't know exactly what the mileage will be when it's empty but I'm guessing a little over 800 at 15mpg.
Closing thoughts: This project would be a lot easier with a truck lift. As it was, there was very little room to work under the truck. Having an "extra set of hands" will also make this project a lot easier to complete.
Overall I'm very satisfied with this product, and I will not have to stop to fillup "enroute" with the 5th wheel loaded, for most trips. I will also be able to complete most local trips without buying diesel at an unfamiliar station, at their inflated prices...
1. Get you OEM tank as close to empty as you can. This will make it a lot easier to handle, and get the hoses off while it is lowered half way. Jack up the rear of the truck, and put it on jack stands, for more room. Use the floor jack with a 4X4 block on it to hold the tank up while unbolting it. The bracket bolts, holding on the tank, can be a little tricky to get to and you will need a good "deep socket" to get them off.
2. I took the fill hose and vent hose off from the "fill neck" before lowering the tank. Releasing the feed and return lines can be a little awkward as you have to compress the inner catches, on the connectors, while "wiggling" them off. In fact, I ended up taking the "pickup" assembly out of the tank, while the tank was half way down, so I could get better access to the front connector. Be careful that you don't damage the pickup assembly or the float while taking it out.
3. The instructions say to bend the float arm down so that it lays flat with the bottom of the pickup assembly. I did not find this necessary, as the float was already in that position.
4. Put the outer strap mounts into their notches before you put the new tank in. There is very little space between the frame and the tank, after it is in position. Jack the new tank up, about halfway, to get it close enough to attach the fill and return lines (they just snap back on). I didn't have to modify the fill and return lines (lengthen or shorten) to get them to go back on.
3. After the hoses are connected, jack it into the final mount position. The bolts supplied with the tank, for the brackets, are "too long" (the unthreaded shanks aren't necessary) so I had to replace them with new bolts, with no unthreaded shank to them (threaded all the way to the head). Once again, getting the nuts onto the mount bolts is a little tricky (especially the front one) as there is very little space to work in.
4. You will have to cut your fill hose, and vent hose to fit the fill neck, as the tank sits higher. Also, I had a slight "crimp" in the fill hose as the fill neck on the new tank is longer then the stock neck, and is angled up at about a 45 degree angle. This puts a low point in the fill hose between the fill neck and the tank, but it was not a problem filling the tank full, after the install.
5. I put 10 gallons of diesel in the tank. That did not register much at all on the fuel gauge. Went to the station and put an additional 46. 25 gallons in for a total of 56. 12 gallons. You might get more in if the back of the bed was a little more level. but with the bed unloaded, it angles down toward the front.
6. The DTE computer will not work with this install. It goes up to about 480 "distance till empty" and stays there until the float starts to drop. Then it gives a "false" reading, as it is figuring this on a 35 gallon tank, not a 57 gallon one. This is a small concession for getting a bigger tank.
7. I have put about 470 miles on the vehicle since the install. The fuel gauge reads just about 1/2 full. Don't know exactly what the mileage will be when it's empty but I'm guessing a little over 800 at 15mpg.
Closing thoughts: This project would be a lot easier with a truck lift. As it was, there was very little room to work under the truck. Having an "extra set of hands" will also make this project a lot easier to complete.
Overall I'm very satisfied with this product, and I will not have to stop to fillup "enroute" with the 5th wheel loaded, for most trips. I will also be able to complete most local trips without buying diesel at an unfamiliar station, at their inflated prices...
