I have a VXL rustler and I had a similar problem when I tried a True RC 4s 5000 pack, I tried dremeling the hell out of the battery compartment and after getting tired of the burning plastic smell, I deceided to install the pack on its side. I drilled holes in the bottom of the battery compartment and used zip ties to secure the pack...I have had no issues with the pack moving and I charge the pack while in the rustler.