well, its good that u take it apart and learn how it works. but according to what u discribed it seems that the car if fine. i have the 1/8 dm1 nitro.. and it doesnt have a center diff. the rules for 1/8 gt races it doesnt allow center diff, so the car is built to specs.... on road cars have a very thick front diff, i think it makes it turn better on the trottle, some of the racers in my club said that their car with out front diff turn faster on the trottle....

my nitro dm1 has a so thick front diff that when i turn the wheels it slows down a lot.