I read about the auxiliary diesel tank on your discussion page. I used a small gas (now diesel) tank out of a japanise car. Its rectangle and holds about 11 gals. I made a frame and set it in the far right side nearest the diesel filler neck. I have an electric fuel pump, that when turned on fills the main tank. I put a Y valve in the vent hose and that is how its transfered. I dont turn the pump on till the main tanks low fuel lite comes on. I also have a small red lite wired in with the switch so that I remember to shut off the transfer of diesel when the auxiliary take is emptney. I put the switch and lite in the ashtray because I dont smoke. This is how I did it. If you plan on making your own please use your own idea's. I wrote this for reference only, not as a guide. My 1980 300SD can now go a long long way between fill ups. I also can check fuel prices before I leave home so as to get the most an cheapest diesel fuel per tanks full.