get a 4wd transfer case and somehow rig it on there.....

that's the only way u can fix ur problem.... that i know of...

Cept mabye newer better tires....or putting huge rocks in ur engine bay to put wieght on it, then again the litl d-series couldn't move it all with the extra weight....

Guess u'll have to deal with it like the rest of us...

Sry if this didn't help....