Horrible vibration from rear
03-05-2017, 02:33 PM
#1
Horrible vibration from rear Hey guys,
Had a crazy vibration coming from the rear after I did my LS7 clutch, CS MM/TM/DM and shifter bushings and hurst shifter but then it went away after about 10 min of driving. Car felt like driving on a cloud after that until a couple weeks ago when the vibes came back. It's bad enough I can't see anything out of the rear view mirror.
I have had clicking in the rear in the past which makes me think axles. I just ordered voodoo's carrier bearing so that should rule out the d/s to an extent. When I did the clutch, I wiped a good bit of grease out from the heat shield surrounding the rear d/s cv that connects to the diff. Is there a way to open that up and add grease or service it? Diff has whined since I've had the car. 128k miles on the car. It's an 05.
Does anyone know part numbers for the V1 axles?
Thank in advance for any suggestions or help.
Derek
Had a crazy vibration coming from the rear after I did my LS7 clutch, CS MM/TM/DM and shifter bushings and hurst shifter but then it went away after about 10 min of driving. Car felt like driving on a cloud after that until a couple weeks ago when the vibes came back. It's bad enough I can't see anything out of the rear view mirror.
I have had clicking in the rear in the past which makes me think axles. I just ordered voodoo's carrier bearing so that should rule out the d/s to an extent. When I did the clutch, I wiped a good bit of grease out from the heat shield surrounding the rear d/s cv that connects to the diff. Is there a way to open that up and add grease or service it? Diff has whined since I've had the car. 128k miles on the car. It's an 05.
Does anyone know part numbers for the V1 axles?
Thank in advance for any suggestions or help.
Derek
03-05-2017, 03:36 PM
#2
Can you be more specific about the vibration? Is it engine RPM dependent or wheel speed dependent?
My two main suspects are LS7 clutch bolt torque and driveshaft coupler bolt torque. Did you torque those to spec with a torque wrench in the proper pattern, with at least one drop of blue loctite? Axles can also cause vibration, but you didn't touch those when you did the installation.
My two main suspects are LS7 clutch bolt torque and driveshaft coupler bolt torque. Did you torque those to spec with a torque wrench in the proper pattern, with at least one drop of blue loctite? Axles can also cause vibration, but you didn't touch those when you did the installation.
03-05-2017, 05:24 PM
#4
Dude. You installed the flywheel using a pneumatic air wrench and torqued the pressure plate on by feel? And you're asking "why vibration?"
Those components are sensitive to torque and may generate damaging levels of vibration with more than ±10% difference in torque. For a skilled technician with clean threads and full range of motion, torquing by feel has a ±25% margin of error. Impact wrenches are vastly worse--it's easy to overshoot by 100-300%.
If the problem existed before as you said, I think you did yourself a disservice because now the problem has been masked or compounded by a potentially worse issue. Why would you drive on something that's vibrating so badly you can't see out the window? Problems don't fix themselves by abusing the hardware. The temporary loss of vibration was probably a sign that bolts loosened and/or damage occurred.
I checked your post history and noticed you bought a used clutch that was damaged in shipping. I think you need to start by removing the clutch and flywheel and get them checked/balanced. Then reinstall everything (including the driveshaft coupler) using a calibrated torque wrench. Once you've eliminated the driveline as the problem and the car is safe to drive, we can look at the axles and see if there's a problem with the CV joints.
Those components are sensitive to torque and may generate damaging levels of vibration with more than ±10% difference in torque. For a skilled technician with clean threads and full range of motion, torquing by feel has a ±25% margin of error. Impact wrenches are vastly worse--it's easy to overshoot by 100-300%.
If the problem existed before as you said, I think you did yourself a disservice because now the problem has been masked or compounded by a potentially worse issue. Why would you drive on something that's vibrating so badly you can't see out the window? Problems don't fix themselves by abusing the hardware. The temporary loss of vibration was probably a sign that bolts loosened and/or damage occurred.
I checked your post history and noticed you bought a used clutch that was damaged in shipping. I think you need to start by removing the clutch and flywheel and get them checked/balanced. Then reinstall everything (including the driveshaft coupler) using a calibrated torque wrench. Once you've eliminated the driveline as the problem and the car is safe to drive, we can look at the axles and see if there's a problem with the CV joints.
03-05-2017, 05:57 PM
#5
Buddy, you have looked WAY too far into my post.
I was talking about impact driving the driveshaft bolts as I did not see a reason to torque those. That was not my first clutch install and I know how to use a torque wrench.
With the damaged clutch post, I did not use that clutch because it was an LS9 clutch and I did not have $800 for a flywheel to adapt that clutch. Furthermore, only the slave cylinder was damaged with that clutch which is irrelevant but just wanted to point out you did not read the entire post.
The vibes are driveline related, no doubt. You are fairly versed with information on this vehicle and your input is welcomed but I would prefer you focus on the stated problem rather than question my wrench turning abilities.
I was talking about impact driving the driveshaft bolts as I did not see a reason to torque those. That was not my first clutch install and I know how to use a torque wrench.
With the damaged clutch post, I did not use that clutch because it was an LS9 clutch and I did not have $800 for a flywheel to adapt that clutch. Furthermore, only the slave cylinder was damaged with that clutch which is irrelevant but just wanted to point out you did not read the entire post.
The vibes are driveline related, no doubt. You are fairly versed with information on this vehicle and your input is welcomed but I would prefer you focus on the stated problem rather than question my wrench turning abilities.
03-05-2017, 07:16 PM
#6
Spec...If you had grease on heat shield above the rear CV joint where it meets the diff..You probably lost grease from that joint which can cause vibrations and noise.. you can unbolt that CV joint from the diff... Drop it down and remove the rear Inspection plate. See if the joint is packed full of grease. If not, add some to the front and back of the joint. Be very careful not to let the joint fall apart. If you add grease you must use cv joint grease which should say moly somewhere on the tube. High pressure moly grease. Torque those bolts to 44lbft
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03-06-2017, 09:32 AM
#8
Voodoo and vroom, thank you for the input.
I am guessing the inspection plate comes off with a screw driver and a few light hammer taps kinda like the middle d/s cv?
Also, I didn't make it clear earlier, I stopped driving the V a while back when the vibes got bad again. Just got the funds together to start chasing the problem.
I am guessing the inspection plate comes off with a screw driver and a few light hammer taps kinda like the middle d/s cv?
Also, I didn't make it clear earlier, I stopped driving the V a while back when the vibes got bad again. Just got the funds together to start chasing the problem.
03-22-2017, 08:28 AM
#11
03-28-2017, 07:52 PM
#13
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Did some investigating tonight.
Despite seeing this a while back:
... my rear CV does not appear to be dry like SRK's was. There was enough grease in there that I couldn't get the rear cover plate off - the suction of the grease seemed like it was going to pull the CV apart as I tried to pull off the cover, and I was afraid I wouldn't be able to get the damn thing back together if that happened.
A couple crappy pictures (taken in an unlit parking lot at 8pm, trying to hold the CV cover plate open with one hand and operate the camera with the other
):
That's the rear CV on driveshaft #1, which is all stock. It's currently in a box in my trunk. A number of weeks back I removed that driveshaft and installed driveshaft #2, which is the one that has a VDC poly carrier surround, and has been shortened by 1/2". Swapping out the driveshafts yielded no change in the vibration/noise issues, so I figured it was a long shot that I would find the rear CV was dry. Just seems unlikely that the rear CVs on both axles had lost their grease to the point that they generated identical (as far as I can tell) vibrations & noise, but I figured it couldn't hurt to take a look.
Despite seeing this a while back:
... my rear CV does not appear to be dry like SRK's was. There was enough grease in there that I couldn't get the rear cover plate off - the suction of the grease seemed like it was going to pull the CV apart as I tried to pull off the cover, and I was afraid I wouldn't be able to get the damn thing back together if that happened.
A couple crappy pictures (taken in an unlit parking lot at 8pm, trying to hold the CV cover plate open with one hand and operate the camera with the other
):That's the rear CV on driveshaft #1, which is all stock. It's currently in a box in my trunk. A number of weeks back I removed that driveshaft and installed driveshaft #2, which is the one that has a VDC poly carrier surround, and has been shortened by 1/2". Swapping out the driveshafts yielded no change in the vibration/noise issues, so I figured it was a long shot that I would find the rear CV was dry. Just seems unlikely that the rear CVs on both axles had lost their grease to the point that they generated identical (as far as I can tell) vibrations & noise, but I figured it couldn't hurt to take a look.
03-28-2017, 09:32 PM
#14
Grease suction is not why the inspection plate is stuck on. Some are wedged pretty hard and some have some half assed factory glue crap on the cork gasket. The joints we experience that we call "dry"... The grease is like stiff clay and non glossy.
04-01-2017, 11:24 AM
#17
Thanks for posting your continued efforts AAIIC. I know this has been a major pain and I share your frustrations believe me.
But, we've been bouncing around in a couple of threads on this subject and I've kinda lost track of where you're at with this.
IIRC, you too felt that your driveshaft was too long and didn't like the fact that you had to compress it to get it into the car.
IIRC, you shortened your original CS 8.8 adapter or were looking into it but you were told you can't shorten it because it will affect the function of the CV if you do and the adapter is already as short as it can be...So you shortened and rebalanced the driveshaft a 1/2 inch. Does it slide into the car without needing to compress it? And if I'm reading this right, it didn't make any change in how your car vibrates?
Question....have you played with the pinion angle by shimming the cradle? I did notice significant changes when I did this but it didn't completely go away....it just muffled them a little and moved the vibrations up the mph scale.
Also, did you ever figure out why you were getting the massive run-out you found in the video posted in this thread?
https://ls1tech.com/forums/cadillac-...ration-10.html
But, we've been bouncing around in a couple of threads on this subject and I've kinda lost track of where you're at with this.
IIRC, you too felt that your driveshaft was too long and didn't like the fact that you had to compress it to get it into the car.
IIRC, you shortened your original CS 8.8 adapter or were looking into it but you were told you can't shorten it because it will affect the function of the CV if you do and the adapter is already as short as it can be...So you shortened and rebalanced the driveshaft a 1/2 inch. Does it slide into the car without needing to compress it? And if I'm reading this right, it didn't make any change in how your car vibrates?
Question....have you played with the pinion angle by shimming the cradle? I did notice significant changes when I did this but it didn't completely go away....it just muffled them a little and moved the vibrations up the mph scale.
Also, did you ever figure out why you were getting the massive run-out you found in the video posted in this thread?
https://ls1tech.com/forums/cadillac-...ration-10.html
04-01-2017, 08:54 PM
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Also, did you ever figure out why you were getting the massive run-out you found in the video posted in this thread?
04-04-2017, 06:11 AM
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I did just the driver side rear wheel bearing, as it sounded rough on the mechanic's stethoscope when I had the car rolling in 2nd gear on jack stands.
At this point I think it's in the output of the transmission - bad bearing I guess? I wish I knew for sure!
At this point I think it's in the output of the transmission - bad bearing I guess? I wish I knew for sure!