lets play guess that grinding sound
03-25-2012, 09:29 PM
#1
lets play guess that grinding sound I'm 100% stumped. Right before I put the car away for winter I had a grinding sound coming from the car...was a faint metal on metal sound, like metal rubbing against another piece of metal while rotating...similar to that sound you get when you go over rumble strips, or when they've stripped that first layer of pavement from the road and you drive over it...but the sound is obviously much quieter.
Anyways mechanic said rear sounded quiet...but the tail of the trans was grinding...fast forward to today, I've swapped the trans and still have the exact same sound.
I thought the DS might be rubbing the safety loop as there is marks on the driveshaft in that area...so I just put painters tape on the shaft where the marks are to see if this was infact the issue; however the tape is untouched.
Wheels don't look like they're near anything to rub, and I've swapped the rims/tires to eliminate that possibility...still nothing.
I'm stumped...what the heck else could sound like it's grinding? Seems like you can hear the noise sometimes on accel, sometimes on decel...and the odd time if you put the car in neutral and rev it very lightly (i.e blip the throttle barely)...all instances seems to occur with extreme light throttle, at higher throttle I'm sure its blended in with exhaust/motor noise.
Who has ideas?
I've pulled the belt and spun the pullies, most noise I hear is a squeaking
Alternator pulley.
Tires all turn freely, no marks on the rotors..I'm 100% out of ideas...I thought maybe even the timing chain, but my KR sensors pick up 0.1-0.5 degrees of knock at best and it's random...and not usually when I can make out the grind/whine
The LAST thing I noticed while playing under the car today was that the torque arm is resting against the tunnel when I load the suspension up with the jack on the rear axle. I have a ford 8.8 rear end, Im guessing the mount for the torque arm might be a hair further over than stock for this to happen? In any event, is it possible for the torque arm to basically transmit the sound of the rotating gears through the car and basically amplify it making it sound as though something is grinding? Kinda similar to using a stethoscope on the diff? I'd say about 3/4 of the arm rests on the tunnel.
Anyone have any ideas about anything?
Anyways mechanic said rear sounded quiet...but the tail of the trans was grinding...fast forward to today, I've swapped the trans and still have the exact same sound.
I thought the DS might be rubbing the safety loop as there is marks on the driveshaft in that area...so I just put painters tape on the shaft where the marks are to see if this was infact the issue; however the tape is untouched.
Wheels don't look like they're near anything to rub, and I've swapped the rims/tires to eliminate that possibility...still nothing.
I'm stumped...what the heck else could sound like it's grinding? Seems like you can hear the noise sometimes on accel, sometimes on decel...and the odd time if you put the car in neutral and rev it very lightly (i.e blip the throttle barely)...all instances seems to occur with extreme light throttle, at higher throttle I'm sure its blended in with exhaust/motor noise.
Who has ideas?
I've pulled the belt and spun the pullies, most noise I hear is a squeaking
Alternator pulley.
Tires all turn freely, no marks on the rotors..I'm 100% out of ideas...I thought maybe even the timing chain, but my KR sensors pick up 0.1-0.5 degrees of knock at best and it's random...and not usually when I can make out the grind/whine
The LAST thing I noticed while playing under the car today was that the torque arm is resting against the tunnel when I load the suspension up with the jack on the rear axle. I have a ford 8.8 rear end, Im guessing the mount for the torque arm might be a hair further over than stock for this to happen? In any event, is it possible for the torque arm to basically transmit the sound of the rotating gears through the car and basically amplify it making it sound as though something is grinding? Kinda similar to using a stethoscope on the diff? I'd say about 3/4 of the arm rests on the tunnel.
Anyone have any ideas about anything?
04-16-2012, 12:00 PM
#2
Bump...I'm pulling my hair out...should have a tunnel mount torque arm being installed next wednesday...HOPING that will fix the issue, but who knows if the tq arm resting against the tunnel of the car right now is what's causeing the grinding sound?
I can't really hear much if I drive the car up to speed, shut it off and let it coast...as it slows down there is some kinda noise, but its hard to explain
I can't really hear much if I drive the car up to speed, shut it off and let it coast...as it slows down there is some kinda noise, but its hard to explain
