I just got a evo VIII about a month ago from a dealership by charlotte nc, and I absolutely love the car. I traded in a 07 civic si for it, and the difference is huge. I put a test pipe on it and a halman mbc. It had work done to before I bought it and had a tune. It has been running fine till last night. I was driving home from new york and the car started making a weird sound. It started making a metal rattling noise like a loose exhaust part, and vibrating like crazy. I am worried that my trasfer case might be toast. I did weld a heat shield on my test pipe, so if it broke loose, that would explain the rattle, but not the ridiculously large amount of vibration. I will check my transfer case oil level today and my exhaust system for rattling. If anyone has any insight as to what the noise could be, and what a dying transfer case, or loose driveshaft sounds like, please let me know. I am new to all wheel drive, so all this is new to me.

 

sounds like that shield might be hitting the driveshaft.....take it off..you dont need it...

 

You would really be surprised how much rattle a loose exhaust part can make. For example: my cat had one of the welds fail right after I had my timing belt, tensioners, etc. replaced. I thought the timing belt was not tensioned properly, however, when I changed the cat out with a test pipe, the vibration disappeared. The harmonics from the vibration were so loud that I could hardly hear the radio cranked up. Not to mention the virbration coming through the shift knob and pedals. I would definitely start with the heat shield...

 

I only welded the shield on so if i got pulled over, and the cop looked under the car it would look like a cat was in place. I looked under there without jacking it up, and it looks like it is still in place. It vibrates so bad, it feels like the car is falling apart. It didnt happen after a hard launch or anything, so it is hard for me to beleive something broke, I think either t case fluid is low, eshaust is loose or both. I will keep everyone posted, and keep the suggestions coming in.

 

took the evo for a ride at lunch and it has to be driveshaft or exhaust related. it is coming from the center of the vehicle, and the faster it goes, the more noise it makes. If the car is not in gear, almost no noise, just an occasional rattle. I shook the eshaust a few times, and it seems solid. What could cause a drive shaft to come loose, unbalanced, or break while crusing on the highway?

 

You need to be more specific, man. When does the sound come in/off. When does the car shake, what gear/ speed, on/off gas/clutch, steering wheel shake, etc etc.

 

makes noise when car is in motion, unless car is not in gear (clutch pushed in, or in neutral), vibration comes on randomly, but seems to coinside with amount of vibration that is typically felt with acceleration. Low speeds not so much vibration,, high speed, more vibration. The sound is like a metal chain dragging, or something metal hitting something else metal, but not very solid, very exhaust rattle sounding. Is it possible for the driveshaft to be unbalanced and it is hitting the exhaust as it rotates? What could cause it to become unbalnced?

 

Check under the car to make sure nothing is hitting the drive shaft.

 

well from what he's saying its more than likely the driveshaft, its possibly bent at one of the knuckles...or its something with his transfercase...cause he said it only does it in gear which indicates the driveshaft......and it gets louder w/the faster he goes which points to both driveshaft and possibly crankcase

 

must be your heat shield

 

I drove almost 2000 miles with the heatshield and no problems till last night, about 11 hours into my drive home. Problem seems much worse today. I cant wait to get this thing up in the air to check it out.

 

check your driveshaft and transfercase for sure man....and let us know what you find

 

I looked under the car yesterday, and couldnt see anything unusal at first. I tightened the bolts on the exhaust, but they were already pretty tight. I looked on the drive shaft, the exhaust to see if there was anywhere that looked like they had touched, and by the second knuckle i guess it would be called, where it has a support bolting it to the floor, it looks like the exhaust and drive shaft support have been hitting eachother. Also, on the very last segment of the drive shaft I noticed there was a band of very clean metal, while the rest was quite dirty, almost like there was a band, or weight that was there that is no longer there. Is it possible that there was a hose clamp there or something similiar used to balance it? I have heard of people using things lke that to balance a driveshaft. Do you guys think I should just take it to the dealership, I have a test pipe on there, and I cant put my cat on.

 

The first thing I would do is have a friend come over and rev the engine while you have your head down underneath the car (of course make sure its in neutral). If one of the welds on the heat shield have failed, you should be able to hear the ratttle. An exhaust vibration will more than likely feel like it is coming from the center of the car, since that is basically where the cat, or heat shield in your case is located. Hopefully this is it, since a driveshaft replacement will be much more of a headache...good luck

 

this rattle, is not like an exhaust rattle, it is hardcore. it shakes the car real bad, and i can feel something hitting the floorboard. When it is shaking hard, it feels like someone is punching the bottom of my seat from under the car, and it goes faster as speed/rpm increaces