Car vibration issue - need help
02-09-15, 12:35 PM
#1
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Car vibration issue - need help
Hey guys i have a 1998 sc400 and i need help. When i am traveling at 40-45 mph i feel a vibration and its only when i am traveling 40-45mph any other speed its smooth. It feels like it is coming from underneath. If you could help in anyway i would greatly appreciate it thanks.
02-10-15, 09:11 AM
#3
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02-10-15, 09:13 AM
#4
Hey guys i have a 1998 sc400 and i need help. When i am traveling at 40-45 mph i feel a vibration and its only when i am traveling 40-45mph any other speed its smooth. It feels like it is coming from underneath. If you could help in anyway i would greatly appreciate it thanks.
02-10-15, 09:23 AM
#5
The tranny mount compresses as it breaks down. There's nothing to fix, so it should be replaced if it's worn. Mine still had some life left in it when I replaced it (want a cheap one? 
), but you have to remove it to be able to tell and I figured there's no point going to all that trouble without a new one on hand.
ashtray, I would think your motor mounts or suspension components are more likely to blame. I'd be surprised if the transmission mount can cause that much vibration.
), but you have to remove it to be able to tell and I figured there's no point going to all that trouble without a new one on hand.ashtray, I would think your motor mounts or suspension components are more likely to blame. I'd be surprised if the transmission mount can cause that much vibration.
02-10-15, 01:26 PM
#6
Pole Position
Get an alignment, check suspension, get a trans mount & make sure your tires have equal pressure in all 4 wheels. But like stated, probably suspension issues. My car currently has 100,8xx. It is a highway warrior. No vibrations. Accept the ones due to road surfaces and the Zeal Coil Overs don't help lol.
Keep us posted.
Keep us posted.
02-10-15, 06:53 PM
#7
Driver School Candidate
Check the center support bearing on the driveshaft. If you can hear some slight clunking around when shifting from Park to any other gear, OR a quick stab of the throttle, the bearing is worn out. Mine also has an electric car sound coming from the trans tunnel at very slow speeds. While you are under the car, check out the transmission mount as well. Both of these items are common failures. My car needs both.
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02-10-15, 08:57 PM
#8
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Replace the transmission mount
Had this problem on my 92 sc400 and an LS400 1999. Replacing the tranny mount takes about 15 minutes. I think the mount was about $86.
Make sure you take a jack and take the weight off of the mount before you release the bolts.
Easy peasy
Make sure you take a jack and take the weight off of the mount before you release the bolts.
Easy peasy
02-12-15, 09:11 AM
#9
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Thread Starter
The tranny mount compresses as it breaks down. There's nothing to fix, so it should be replaced if it's worn. Mine still had some life left in it when I replaced it (want a cheap one? ), but you have to remove it to be able to tell and I figured there's no point going to all that trouble without a new one on hand.
ashtray, I would think your motor mounts or suspension components are more likely to blame. I'd be surprised if the transmission mount can cause that much vibration.
), but you have to remove it to be able to tell and I figured there's no point going to all that trouble without a new one on hand.ashtray, I would think your motor mounts or suspension components are more likely to blame. I'd be surprised if the transmission mount can cause that much vibration.
Get an alignment, check suspension, get a trans mount & make sure your tires have equal pressure in all 4 wheels. But like stated, probably suspension issues. My car currently has 100,8xx. It is a highway warrior. No vibrations. Accept the ones due to road surfaces and the Zeal Coil Overs don't help lol.
Keep us posted.
Keep us posted.
Check the center support bearing on the driveshaft. If you can hear some slight clunking around when shifting from Park to any other gear, OR a quick stab of the throttle, the bearing is worn out. Mine also has an electric car sound coming from the trans tunnel at very slow speeds. While you are under the car, check out the transmission mount as well. Both of these items are common failures. My car needs both.
Found one for 56$ brand new thanks a lot!
02-16-15, 04:47 PM
#10
So the issue on my car was that my passenger front brake caliper completely ate $#!T and seized frozen as compressed as it could on the rotor. So basically every time my wheel turned a revolution the caliper would skip or pop open and clamp back down. I have no idea how this happened, probably that cinder block I hit on the damn highway. Anyway, my bearing in that wheel is also shot. Insurance has me covered. Heres to new brakes/rotors and bearings.
02-17-15, 01:07 PM
#13
Usually vibration at a certain speed is caused by a rotational part being out of balance, usually tire/wheel. Could be a separated belt in the tire, bent wheel, bent or out of balance drive shaft. A warped rotor will usually only cause pulsation when brakes are applied, but they can do funky things if they are real bad.
02-25-15, 07:54 PM
#14
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Thread Starter
So the issue on my car was that my passenger front brake caliper completely ate $#!T and seized frozen as compressed as it could on the rotor. So basically every time my wheel turned a revolution the caliper would skip or pop open and clamp back down. I have no idea how this happened, probably that cinder block I hit on the damn highway. Anyway, my bearing in that wheel is also shot. Insurance has me covered. Heres to new brakes/rotors and bearings.
Usually vibration at a certain speed is caused by a rotational part being out of balance, usually tire/wheel. Could be a separated belt in the tire, bent wheel, bent or out of balance drive shaft. A warped rotor will usually only cause pulsation when brakes are applied, but they can do funky things if they are real bad.
02-26-15, 08:30 AM
#15
If its a constant vibration that progressivly gets worse the faster you go, then its something to do with your wheels (likely balance, but as Ashtray showed us it could be a few other things like a brake caliper).
But if the vibration is only at certain speeds (ie, 40-45 as OP stated) then its likely the transmission mount. I had this same issue in my previous '99 and swapping out the tranny mount cured ALL vibration issues I had. It was a stupid easy job to do, and worth doing on ANY sc over 80k regardless of whether you think you have vibrations or not. Once changed, you car will run even smoother than you thought it did before
..same as the tranny mount, the engine mounts are made the exact same way, so if your tranny mount needs replacing, then likely your engine mounts do too.
But if the vibration is only at certain speeds (ie, 40-45 as OP stated) then its likely the transmission mount. I had this same issue in my previous '99 and swapping out the tranny mount cured ALL vibration issues I had. It was a stupid easy job to do, and worth doing on ANY sc over 80k regardless of whether you think you have vibrations or not. Once changed, you car will run even smoother than you thought it did before
..same as the tranny mount, the engine mounts are made the exact same way, so if your tranny mount needs replacing, then likely your engine mounts do too.