Ive got a 96 4runner(auto). it runs great except for a rattle that seems to come from under the truck, right about the driver seat area.i can hear it when i go up a hill, when i accelerate, any tiem the rpm hits 1800 or 2200. it sounds like a drumer hiting on an aluminum plate. i checked all the heat protectors i could see, and it just passed a mechanincal inspection for me to get it plated, and the mecanik didnt see anything wrong under the truck. WHAT COULD THIS BE?

 

I will speculate the u joints in the drive shaft. seems to have been the same thing i was expierencing when mine went bad. mine was so bad i could just grab on it and shake it and could tell the drive shaft was bad. I confirmed it by jacking it up and having someone push on the gas while i watched, but for saftey reasons this is not wise!

 

the drive shaft for the rear does move a little. I guess its hard to explain the tun rattle sound just with words. It seems an odd sound for a drive shaft. But I will check again. If anyone has suggestions, feel free.

Thanks looking4fish,hope you catch some!

 

I just checked the u joints and drive shaft, all is perfect. no play or leaks.i took a wrench and tapped along anything that could be tapped, and i found nothing. this is baffling!

 

I had the same thing happening on mine… It was a catalytic converter. It was still functioning fine but would rattle under load, just as you have described.

 

I had similar symptoms on my 95 2nd gen. Had to unbolt the cat and literally turned it upside down and shook out a piece of metal-muffler guys implied it was unburned fuel that had solidified in the cat... sure enough the rattle was gone.

They did similar method as looking4fish describes-someone was under the cat while another tech "goosed" the accelerator-they then showed me same thing to get my permission to drop the cat and shake it out.

 

heh thanks guys. i will get under there and check it out.

cheers...

 

Marbles in a coffee can, thats usually what it sounds like.

 

Make sure your hand brake cable is properly adjusted.

 

mine was doin that as well - it was the shield around the cat converter, the bolt had come out so i rigged up some poly spacers with new bolt and rattle is gone

 

Same here. Mine was the heat shield around the cat. I took my shield off and the rattles went away.

 

Is it a hard job to do? Can i handle it with a simple tool set and the hanes manual? If i take off the heat cover, is that dangerous, should I replace it? Thanks brothers. You really got my back on this, and thats cool!