You said you put in new batterys, so they are alkaline cells? The holder that comes with an older traxxas are notorious for causeing glitches from bad connections. The spring loaded plastic holder is the cause of many runway cars. Replace the battery holder.
XRAY NT1 2014 NOVA KEEPON DX3R
MIKE PARKER PRESIDENT
NORTHERN INDIANA TEAM RACING ORG. MIDWEST SERIES TEAM DIRECTOR