Thinking out loud about my driveline/driveshaft.
06-04-2011, 09:50 PM
#1
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Thinking out loud about my driveline/driveshaft.
Going to empty my mind and ramble a small bit, get my thoughts out.
I have a stock T-56/driveshaft/3.42:1 rear/suspension.
Mods are in the sig, estimated 425 rwhp, I'll find out when I dyno.
Getting up around 90 MPH, I notice some vibration. I assume it's the driveshaft, but it wouldn't hurt to get the balance on my tires checked too. I have not tried rotating my driveshaft 180* yet.
I was driving my buddy's '94 w/ a cammed LS1 conversion, and his driveshaft let go on me on me doing a test run at ~100 MPH. Pretty scary as you can imagine. No loop on his car. I do have one on mine.
I think we will all agree that I am on borrowed time with my stock rear end at this power level, once I put some grippy tires on. A good driveshaft from Dennys etc. (I saw the sticky) is going to run me ~$400+. It's also likely that I will need to get a shorter driveshaft when I eventually swap rears to a 12-bolt/9"/D60 (Haven't researched which is best for me yet).
Not sure how much it would cost to get my driveshaft balanced and the u-joints replaced. That might be the best interim solution. Every time I get up in speed and feel some vibes, all I can think about is that driveshaft letting go on me. Again.
...he's not pointing any fingers. (That's me holding the section that broke out of the middle of his driveshaft).
I have a stock T-56/driveshaft/3.42:1 rear/suspension.
Mods are in the sig, estimated 425 rwhp, I'll find out when I dyno.
Getting up around 90 MPH, I notice some vibration. I assume it's the driveshaft, but it wouldn't hurt to get the balance on my tires checked too. I have not tried rotating my driveshaft 180* yet.
I was driving my buddy's '94 w/ a cammed LS1 conversion, and his driveshaft let go on me on me doing a test run at ~100 MPH. Pretty scary as you can imagine. No loop on his car. I do have one on mine.
I think we will all agree that I am on borrowed time with my stock rear end at this power level, once I put some grippy tires on. A good driveshaft from Dennys etc. (I saw the sticky) is going to run me ~$400+. It's also likely that I will need to get a shorter driveshaft when I eventually swap rears to a 12-bolt/9"/D60 (Haven't researched which is best for me yet).
Not sure how much it would cost to get my driveshaft balanced and the u-joints replaced. That might be the best interim solution. Every time I get up in speed and feel some vibes, all I can think about is that driveshaft letting go on me. Again.
...he's not pointing any fingers. (That's me holding the section that broke out of the middle of his driveshaft).
06-05-2011, 10:34 AM
#2
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Re: Thinking out loud about my driveline/driveshaft.
The stock steel DS's are know for vibration at higher RPM's where critical frequency becomes a problem. The only reason you aren't seeing the problem at 70MPH is the 3.42 gears. Rebalancing usually doesn't solve the problem. GM actually had a technical service bulletin (TSB - applicable only to cars under warranty, not a "recall") that allowed a lot of owners to get free 1LE aluminum DS replacements when they complained of vibration.
The problem with the aluminum replacements (a lot of LS1 cars have aluminum DS's) is that they will break under high HP. But at 425rwHP you might get by.
I'd just get a Spohn Extreme Duty for $375, and sell it when you upgrade to the 9" rear.
(As I'm typing this, I'm hearing the Top Fuel dragsters running in the Nationals at Englishtown..... pretty loud.... and I am 7 miles from E'town!!!)
The problem with the aluminum replacements (a lot of LS1 cars have aluminum DS's) is that they will break under high HP. But at 425rwHP you might get by.
I'd just get a Spohn Extreme Duty for $375, and sell it when you upgrade to the 9" rear.
(As I'm typing this, I'm hearing the Top Fuel dragsters running in the Nationals at Englishtown..... pretty loud.... and I am 7 miles from E'town!!!)
06-12-2011, 01:24 PM
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Re: Thinking out loud about my driveline/driveshaft.
Oh they are? Well, that stinks to hear, but, is good to know. I hate to drop ~$400 on a driveshaft, but the peace of mind is going to be well worth it after having one come apart at 100 MPH.
I had a dream the other night where I bought one of those driveshafts you mentioned, and all the problems and vibrations went away, and rode like something of fine German engineering, not GM. I know it won't be *that* good, but hopefully it's a premonition to good things.
Thanks for the info.
I had a dream the other night where I bought one of those driveshafts you mentioned, and all the problems and vibrations went away, and rode like something of fine German engineering, not GM. I know it won't be *that* good, but hopefully it's a premonition to good things.
Thanks for the info.
06-13-2011, 07:03 PM
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Re: Thinking out loud about my driveline/driveshaft.
I was reading this thread, and didn't really think about it until now. Having replaced my stock with a tubular k-member, new engine mounts, poly trans mount, and having taken the torque arm in and out, is it possible I may have changed something angle-wise and would require a re-adjustment? If so, where can the adjustment be made?
https://www.camaroz28.com/forums/sho...ighlight=joint
https://www.camaroz28.com/forums/sho...ighlight=joint
06-13-2011, 07:26 PM
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Re: Thinking out loud about my driveline/driveshaft.
Interesting:
http://www.markwilliams.com/driveshafttech.aspx
http://www.markwilliams.com/driveshafttech.aspx
06-13-2011, 07:39 PM
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Re: Thinking out loud about my driveline/driveshaft.
Nothing about this seems like a good idea. 
http://www.driveshaftshop.com/driveshafts-101
Jack Test:
I have a hard time imagining my wheels spinning to "80 MPH" up in the air on jack stands.
I will spin it 180* for the time being, see if that helps any. My tires are 9 years old and the car has sat a lot. I wonder if they are flat-spotted; or if I should get them re-balanced (or, just burn them off and get something new.
)
http://www.driveshaftshop.com/driveshafts-101
Jack Test:
DRIVESHAFT VIBRATION: 101 (not for CV axles)
Most people have trouble determining if the vibration in their vehicle is coming from the DRIVESHAFT or not. There are typically two types of vibration most vehicles would have. A fast cycle vibration or a slow cycle vibration, to help understand this lets say we put a bucket of water on the passenger’s floor. If the vibration in the vehicle produces small ripples on the top of the water this would be considered a fast cycle vibration. This type of vibration is usually a drive train vibration, things like the driveshaft, motor or torque converter. If the vibration puts waves on the top of the water or splashes, this type of vibration is a slow cycle vibration and usually is an axle or tire vibration. People have trouble determining where the vibration in their vehicle is coming from. Try the test below if your not sure.
JACK TEST
A simple way to do this is out the vehicle in question up on jack stands (make sure the vehicle is completely secure), block the front tires and run the vehicle up to the speed you have the vibration. Make sure you use the brake to stop the drive train before you put the car in park if it’s an automatic. If the vibration is a fast cycle vibration you may want to have the DRIVESHAFT checked for balance. This may make no sense to you but you may try indexing the shaft 180 degrees (just pull the shaft off the rear yoke and put it on the opposite way). What this does is change the resonant frequency property of the driveline and in many cases it takes the vibration away. If you have a slow cycle vibration take the tires off the car (make sure you put lugs back on the axle to keep the brake in line) and run the vehicle again. If the vibration is gone you now have to find out if it’s the rim or the tire and good tire shop can help you with that. This is a simple test for any vehicle but please if you’re not completely sure of how to put the car on stands safely bring the car to a certified technician to perform the test. If you want further help with understanding this process or want help understanding vibration problems please call or e-mail us. We live for drive train and will help as much as we can.
Most people have trouble determining if the vibration in their vehicle is coming from the DRIVESHAFT or not. There are typically two types of vibration most vehicles would have. A fast cycle vibration or a slow cycle vibration, to help understand this lets say we put a bucket of water on the passenger’s floor. If the vibration in the vehicle produces small ripples on the top of the water this would be considered a fast cycle vibration. This type of vibration is usually a drive train vibration, things like the driveshaft, motor or torque converter. If the vibration puts waves on the top of the water or splashes, this type of vibration is a slow cycle vibration and usually is an axle or tire vibration. People have trouble determining where the vibration in their vehicle is coming from. Try the test below if your not sure.
JACK TEST
A simple way to do this is out the vehicle in question up on jack stands (make sure the vehicle is completely secure), block the front tires and run the vehicle up to the speed you have the vibration. Make sure you use the brake to stop the drive train before you put the car in park if it’s an automatic. If the vibration is a fast cycle vibration you may want to have the DRIVESHAFT checked for balance. This may make no sense to you but you may try indexing the shaft 180 degrees (just pull the shaft off the rear yoke and put it on the opposite way). What this does is change the resonant frequency property of the driveline and in many cases it takes the vibration away. If you have a slow cycle vibration take the tires off the car (make sure you put lugs back on the axle to keep the brake in line) and run the vehicle again. If the vibration is gone you now have to find out if it’s the rim or the tire and good tire shop can help you with that. This is a simple test for any vehicle but please if you’re not completely sure of how to put the car on stands safely bring the car to a certified technician to perform the test. If you want further help with understanding this process or want help understanding vibration problems please call or e-mail us. We live for drive train and will help as much as we can.
I will spin it 180* for the time being, see if that helps any. My tires are 9 years old and the car has sat a lot. I wonder if they are flat-spotted; or if I should get them re-balanced (or, just burn them off and get something new.
)
06-14-2011, 09:01 PM
#7
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Re: Thinking out loud about my driveline/driveshaft.
Also looks like I may have a spacer I need to take out of my trans mount.
https://www.camaroz28.com/forums/sho...ht=trans+mount
I will be picking up an angle finder tomorrow.
https://www.camaroz28.com/forums/sho...ht=trans+mount
I will be picking up an angle finder tomorrow.
06-14-2011, 09:29 PM
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Re: Thinking out loud about my driveline/driveshaft.
More random thought/information. I spoke with Megan at Spohn today, asked her about what to do when I upgrade to a 9" or 12-bolt. She said I would just need to change out the rear u-joint, and that I could reuse this shaft. Great news!
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