problems with the thunder tiger Stadium 1:10 truck

Hey
So I am completely new to r/c and could use some help. Here is what i have:
1:10 stadium truck(thunder tiger)
1:12 mini trophy truck(hpi)
Onyx100 charger
1500 nimh (7.2v)
3000 nimh (7.2v)
3000 nimh (8.4V)
3300 nimh (7.2v)

Here is my problem when I use the batteries in the hpi mini it runs great. But when I use them in the stadium truck it runs for about 1 min and then the light on the receiver flashes indicating that my battery is dead. Does anyone know what the problem is I could really use you'er help

Hey what's the matter with you 91 guys out there that you don't have some idea for this poor guy. I can't seem to get any reply to my question either. It only takes a second or two to put in ur 2 cents. The guy's a newbie and any suggestions at all will help. However, cplus, you didn't say what happens when the receiver battery 'dead light' comes on. Can you still run the truck or is the battery really dead. If so, sounds like you are pulling a hell of a lot of power which could be a speed controller issue or a short. When this happens is there amazing heat coming out from under the rig?