bell like rattling

Hello All,
I just purchased a 2002 tacoma and am pretty psyched with it for sure.
One issue though is that there is an intermittent rattling when I am in first gear (or reverse) and start to take off. it sounds almost like a small rock tumbling around inside a spinning steel cylinder. has a distinct bell like sound. (imagine a tiny rock bouncing around inside a tiny clothes dryer.) It's coming from beneath the truck bout mid way down. I checked heat shields and they are quite secure and poking at them I doubt they would produce that sound.
Also... the sound goes away very quickly as I accelerate and does not come back till I am stopped and take off again... but.. not all the time. just MOST of the time.
It's like whatever is bouncing around finds a "home" and when I come to a stop dislodges and starts bouncing around when I take off again until it finds a "home" and gets stuck somewhere again.
After doing some tapping with a piece of hardwood I found that tapping the driveshaft rings a bell tone similar to what I am describing.
Could there be something loose in the shaft itself?
Thanks for any input you may have.
-Chris

 

so after some investigation with a lil tapping from a hard rubber mallet I discovered that the front drive shaft had what appears to be a washer tack welded to its side. I believe part of the welding material may have fallen into the drive shaft itself and is rattling around in there. VERY annoying. I wrapped a piece of roofing rubber around the drive shaft and held it in place with a hose clamp to test. It has deadened the bell like ringing and reduced the noise to ticking at low speeds. Still annoying but less offensive. I assume there is no simple way of getting whatever is in the driveshaft out. Was thinking new drive shaft may be the only route.
After driving for a few hundred miles now I noticed a slight vibration between 38 and 45 MPH. Also a slight wobble around 70 MPH smooth as silk at 80 MPH!
I checked the drive shaft and there seems to be no play at the universals but slight play In the Center driveshaft carrier bearing - maybe 3 mm.
Have read that replacing both driveshafts and carrier with a single solid driveshaft may help with both the issues described here.
Any thoughts?!
Thanks!
-Chris

 

So I brought the truck back to the dealership and they replaced the U joints. This took care of the vibration I felt that began at 38 MPH.
However... the front drive shaft pinging is still there. Still sounds like something bouncing around in drive shaft at low speed in 1 st gear. Creeping in traffic in first gear is ANNOYING! once I start really moving and shift in second gear the drive shaft spins much quicker and the sound goes away. So at take off in first gear and also taking off in reverse the pinging is quite loud.
Any ideas? What could possibly be bouncing around in the front drive shaft?

 

the problem is probably not in your driveshaft but in your exhaust pipe. I too have that annoying pinging noise at idle and slow speeds. Ive had it before and kind of forgot about it. but Its actually just the O2 sensor banging around. the problem I had is the nuts rusted almost completely off (but still cling to the threads making it impossible to just pull the sensor off) its a bitch to fix. the last time I had to have the garage cut and drill the original mounting bolts off and drill and tap new holes that we put hex bolts into. first time was behind the cat this time its forward of cat. but i now got frame rust to deal with before the sensor even gets touched. thank god I had that sensor blow off today because I woulda been driving 2 halves of a truck this weekend with the amount of weight I was trying to haul with it. (I haul junk cars in a s-10 trailer I made.)