Mitsubishi Repair: tingling sound from under the vehicle when driving, bunch of keys, rough terrain

Question
My mechanics and myself are going out of our minds trying to figure out what is making a tingling sound iunder the jeep when we are in rough terrain. It sounds like someone left a bunch of keys hanging on a nail on the chassis of the vehiclenear the back of the front wheels. We have put the vehicle up on a hoist and inspected it to no avail. We have inspected the wheels for any loose part and we came up with nothing. Any suggestions given wil be greatly appreciated.

Answer
Arthur: Next time out in the jeep take another person or more with you. Let each person listen and see if they point to another area of the jeep where the sound is coming from. It could be that the sound is not really coming from the chassis or near the back of the front wheels. It might someplace else. So try that as different people hear things differently. Then check out other parts of the jeep. Even inside of the jeep, it might just be something on the order of keys hanging someplace on or in the jeep. Hope this helps and good luck! Linda