Stumbled by some rattling... any possible issues?
 

So I keep hearing something rattle from the middle underneath of my car, I jacked it up and found my cv axle bolts were loose and figured that was it and tightened them. Still getting the same sound, found a crack at the can of my exaust from the pipe (common breaking area) so I welded in a piece from the pipe to the can as support like 951's have and not 944's, did not solve my issue, even with gloves holding the exhaust firm while the car is on, still nothing! I find when I rev the car and let off the gas right before it hits my idle point I will get a bit of a shudder and hear the rattle, could it be my clutch or torque tube? I know it is not the floating gear because the sounds are not coming from the back of the car and it was still making it not engaged in any gear.

Any advice will be greatly apreciated

I had a sound like this at one time. I found the O2 sensor had lost it's cap inside the exhaust pipe. I had to pull the cat. to get it out.
Good luck
OTR

I have some irritating rattles I believe to be caused by two things: Bad motor mounts and the various heat shields around the car. searching while the car is idling I found that the cat heat shield makes a lot of noise and another near the passenger motor mount if I remember correctly. If I put in new mounts I may not have the rattles at all but for now I'm going to remove the cat and install a resonator and replace the heat shielding with heat reflective tape or something.

I know it is not the engine or tranny mounts since the motor and tranny have been rebuilt and and the mounts have recently been replaced. Being under the car today more and more is being unveiled.

Is there a heat shield between the cat and the torque tube? Mine has one, and although I never heard it rattle, the bolt holes were starting to rust out. It might be rattling against the cat or against something else.

try the heat shield above the rear muffler-could be splitting.

I've got the same problem right now with my 83 NA.

I just replaced the trans a few months ago, and the rattling started after I installed the new trans.

It happens only at about 2,500-3,000 RPM, and also when turning left, hard, while accellerating. It sounds like the noise is coming from the right side, about mid-car.

The noise sounds like when the exhaust touches the body/heat shield (when the engine torques over). The motor mounts are relatively new - probably less than 10,000 miles on them, so the engine doesn't move excessively.

I figured it was the heat shield on the cat - and I've moved the exhaust around (positioned it differently) and the cat doesn't appear to be touching the heat shield, but something still rattles.

Like I said, it didn't do this before I changed the trans - it's really bugging me that I can't find it. It's got to be something associated with the trans job.

Lately, I've just been turning up the stereo...

check the rubber exhaust mounts.
I had a rattle in the center of my car & the pig snout shaped rubber mount for the exhaust was laying there on the torque tube

hey look at the knock out plug on the back of the trans case i had the same problem and noise just before the trans let go cuz it wasnt put together right

also if they didnt replace the rear bearings in the trans it will make that noise as well

Thanks for the tips.

My trans should be okay - it came out of a car that had only 79K miles on it.

The noises are all farther forward...

So I found the rattle, I hear the rattling at a dead stop not in gear, when I push in the clutch the rattling stops, does this mean my throw bearings are going? or my clutch? what should I be worried about or nothing at all.

If it's only with the clutch let out and in neutral, it might be the torque tube, either the bearings going bad, or maybe the plastic sleeve between the bearing and the shaft disintegrating. I also have a rattling torque tube at idle when in neutral with the clutch out. When I got both the clutch and the tranny off the torque tube, the bearings felt pretty solid. I did notice there was some play between the splines on the clutch disk and the drive shaft, which allowed the disk splines to clank when I turned the shaft back and forth with the disk on it. I havent fitted the new disk yet to see if it's got a tighter fit on the shaft, but it would be nice if that's all it is for me.

Rattling or grinding with the clutch pushed in would mean a bad throwout bearing, but maybe there's some play in the pivot arm or shaft that is rattling when disengaged.

Thats good to hear, I was beginning to think I was going to have to replace stuff.

Search for 5th gear synchro rattle. I think it was once a recall item for a short period, then just a TSB. Now classified as "normal."

Thanks a lot guys for all your advice/tips, I found the culprit today by failure of a working part. The leaking was coming from the clutch inspection port, the rattling was from the clutch area of the car and my brakes were not stopping as well as they usually do. So I went to go start the car today and my clutch pedal went to the floor, went out side after I stopped the car to inspect and there was fluid dripping under the middle of my car, my slave cylinder blew. Although this was a ****ty situation I have piece of mind now knowing it is not my rear main seal leaking. So I swapped out the cylinder and the rattle is gone, my brakes are stopping better, the pedal feels a lot smoother, and I feel great! The only issue is the city was repairing the street and did not give me any notifications in the area... I bent my control arm and connecting links!!! once one issue is fixed another always arises... oh well I love my car to much to not put up with this stuff!

Thanks a lot guys for all your help

what did your break pedal feel like? I have the same noise right now i thought it was the cat. I drove it on Monday my break pedal feels like there is very little vacuum assist and i noticed when i left a stop light it felt like the clutch engaged then slipped and engaged again real fast.

check your clutch inspection hole, if there is oil dripping from there for me that was a signal my slave cylinder was going, plus my brake pedal was firm and I was still not getting good breaking, and my clutch was kinda mushy.