Db1 or tm2 owners

[gerbil]

Hi I'm just wondering with these design of cars do you have to lock the disused out drive
As I'm playing with a project but at the moment as sound as I put power to the diff in the middle it spins the disused half
If I put a driver to hold it in place it spins to the rear correctly
So how did you guys overcome this problem or does it not do this with a ball diff (center) as mines got a balls diff
Any help is most welcome
Cheers