Can you blow a preout on a HU??

Ok i have a 2400watt amp pushing a 15" DVC sub.  We went out of town and i needed room for travel and pulled the sub out of the car. We started going down the road and i heard static like when your speaker wires touch. I remembered that i didnt tape the speaker wire ends up after unhooking the sub. So i did, got in the car and took our 3 day trip. So we get home i unload car and rehook up the sub. I turn on the tunes and after about 10 seconds i hear a steady beat of  thuds, equal time in between each. This happened no matter how low the bass or even volume was. Only way to stop it was to turn off the HU or unhook speaker. So today i looked through all the hook up, switched out the RCA cables and all was same. Then out of curiousity i hooked up the RCA to the front preout instead of the Rear preouts that they were hooked up to.   Now they work fine. DID I BLOW THE REAR PREOUTS????

you most likely have some damage to the rear preouts . If that is the only component inline then yes if not check all other components that the rca connects to first. good luck man, that sucks.