Vibration Problem That I can't figure out
Thread Starter
Registered User
Joined: Jan 2003
Posts: 7
From: Ridgway, PA
Vibration Problem That I can't figure out
Guys:
I've got a harmonic vibration problem that is driving me and my mechanic nuts. When I purchased this Camaro last fall I intended to turn it into a "track car." It had 66,000 miles on it and a vibration in the drivetrain that I felt should be fairly easy to correct...WRONG!
First let me set the stage. The car has the original 7.5" rear end however I recently replaced the gears with Richmond 4:10's. We've also played with different shims but to no avail. The driveshaft is the aluminum replacement piece from the factory, not the original steel one. I'm not aware if it was ever balanced, but I assume it was before it was shipped. I just purchased a custom adjustable torque arm from S & W race shop. They make a great product and we've played with the angle of the driveshaft/pinion, but again no luck. The rear suspension is stock. I also replaced the panhard bar with a Granitelli product. Wheels are stock 16" and the Goodyear GT II have about 60% of their tread life left.
The vibration symptoms are as follows:
I can run the car to redline in first gear-no vibration at all. The same way with second gear. In third, a "moderate" vibration begins at around 3,500 rpm, say 60 mph and continue until redline, building slightly as I approach 6,000 rpm. When I shift into fourth the moderate vibration will continue up until redline-not necessarily any worse than in third gear. In fifth the vibration changes dramatically and gets much louder and stronger, even at lower rpms. It sounds more of a harmonic rummm, ruummm every second or so and changes as I accelerate or brake. Sixth gear brings up a really strong vibration that permeates through the back of your seat and rattles the literally coin change in the ashtray. It literally feels as if I turned on a seat vibrator! If I drop the car into neutral at about 70 mph and cost downhill the vibration is STILL there, although only at about 70% of what it is when I shift into fifth and give it some gas at that same speed.
I'm running out of patience, does anyone have a suggestion?
Thanks,
Bud
I've got a harmonic vibration problem that is driving me and my mechanic nuts. When I purchased this Camaro last fall I intended to turn it into a "track car." It had 66,000 miles on it and a vibration in the drivetrain that I felt should be fairly easy to correct...WRONG!
First let me set the stage. The car has the original 7.5" rear end however I recently replaced the gears with Richmond 4:10's. We've also played with different shims but to no avail. The driveshaft is the aluminum replacement piece from the factory, not the original steel one. I'm not aware if it was ever balanced, but I assume it was before it was shipped. I just purchased a custom adjustable torque arm from S & W race shop. They make a great product and we've played with the angle of the driveshaft/pinion, but again no luck. The rear suspension is stock. I also replaced the panhard bar with a Granitelli product. Wheels are stock 16" and the Goodyear GT II have about 60% of their tread life left.
The vibration symptoms are as follows:
I can run the car to redline in first gear-no vibration at all. The same way with second gear. In third, a "moderate" vibration begins at around 3,500 rpm, say 60 mph and continue until redline, building slightly as I approach 6,000 rpm. When I shift into fourth the moderate vibration will continue up until redline-not necessarily any worse than in third gear. In fifth the vibration changes dramatically and gets much louder and stronger, even at lower rpms. It sounds more of a harmonic rummm, ruummm every second or so and changes as I accelerate or brake. Sixth gear brings up a really strong vibration that permeates through the back of your seat and rattles the literally coin change in the ashtray. It literally feels as if I turned on a seat vibrator! If I drop the car into neutral at about 70 mph and cost downhill the vibration is STILL there, although only at about 70% of what it is when I shift into fifth and give it some gas at that same speed.
I'm running out of patience, does anyone have a suggestion?
Thanks,
Bud
Registered User
Joined: Oct 2001
Posts: 368
From: Cincinnati, Ohio
I would try swapping in another driveshaft to see if that fixes the problem. I have the same type of vibration that you're talking about and it's the driveshaft that is causing the problem (I've just been too cheap and lazy to get a new one).
Registered User
Joined: Jun 2001
Posts: 96
From: Fuquay Varina, NC USA
Sounds like the vibration is definitely vehicle speed related.
To rule out the rear tires, you can place it on jackstands (careful here!) and remove the rear tires. Start the car and run it up to the desired speed and you'll feel it if it is driveshaft related. You can try rotating the rear universal 180 degrees and try it again. It may be better, may be worse.
I've been through this with my aluminum LS1 driveshaft.
Mine is much worse with the tires mounted but I know some of it is also in the driveshaft.
I recently replaced my pinion seal and found some excess play in the pinion bearing area. I think the crush sleeve possibly relaxed over the years and added some clearance there. I tightened it some when I reinstalled the pinion nut and I hope it helps my vibration a little (haven't got the trans back in yet).
I'm going to try my original steel driveshaft next.
To rule out the rear tires, you can place it on jackstands (careful here!) and remove the rear tires. Start the car and run it up to the desired speed and you'll feel it if it is driveshaft related. You can try rotating the rear universal 180 degrees and try it again. It may be better, may be worse.
I've been through this with my aluminum LS1 driveshaft.
Mine is much worse with the tires mounted but I know some of it is also in the driveshaft.
I recently replaced my pinion seal and found some excess play in the pinion bearing area. I think the crush sleeve possibly relaxed over the years and added some clearance there. I tightened it some when I reinstalled the pinion nut and I hope it helps my vibration a little (haven't got the trans back in yet).
I'm going to try my original steel driveshaft next.
Thread Starter
Registered User
Joined: Jan 2003
Posts: 7
From: Ridgway, PA
Guys:
Thanks for your advice. Another question though, if it was the driveshaft, could that explain why it's not as strong when it's in neutral as oppossed to being in gear at say 70 mph?
I'll try some of the other suggestions, but if you think of anything else let me know.
Bud
Thanks for your advice. Another question though, if it was the driveshaft, could that explain why it's not as strong when it's in neutral as oppossed to being in gear at say 70 mph?
I'll try some of the other suggestions, but if you think of anything else let me know.
Bud
Registered User
Joined: Mar 2001
Posts: 2,667
From: SLC, UT
I'm havign a similar issue with mine. Have you re-checked your backlash on your gears? That's my issue, when we first setup the rearend we set it correctly but I don't believe it was shimmed enough, and the backlash is WAY out now after about 50 miles of driving, I'm going to pull it apart and reset it tonite, hopefully I didn't do any perment damage to anything...
Registered User
Joined: Oct 2002
Posts: 1,035
From: Greenville, SC
This is funny! A few months ago I posted a similar thread with the same kinda problem. Since then Ive had my tires rebalanced. That helped some but Im still getting vibrations around 70mph and up. I think that it may be my driveshaft as well. There is a place near my house that will rebuil or rebalance your driveshafts for you! And its not that expensive!
Thread Starter
Registered User
Joined: Jan 2003
Posts: 7
From: Ridgway, PA
I believe it is an original mount and not a poly one. I'll be heading under the car tomorrow and will check the mount out to be sure. Thanks again for your ideas... keep em coming!
Go Penn State,
Bud
Class of 81'
Go Penn State,
Bud
Class of 81'
Thread Starter
Registered User
Joined: Jan 2003
Posts: 7
From: Ridgway, PA
Guys:
Over the weekend I did switch the driveshafts from the aluminum replacement one to a new steel one with dampner at the end. Unfortunately, it didn't seem to make any real difference.
Next step is to take out the transmission mount which is poly and replace it with a rubber one.
I'll keep you posted,
Bud
Over the weekend I did switch the driveshafts from the aluminum replacement one to a new steel one with dampner at the end. Unfortunately, it didn't seem to make any real difference.
Next step is to take out the transmission mount which is poly and replace it with a rubber one.
I'll keep you posted,
Bud
Registered User
Joined: Aug 2002
Posts: 16
From: tucson, AZ, USA
I have the Identical same problem with my 94 Z. It sets in about 75 or 80 and gets louder the faster I go. I have the stock gears and a T56. I read somewhere that there was a problem with the balance of the shaft in early 4th gens but nothing GM would do anything about I even replaced the U-joints to see if that helped.. it did nothing. As for tires, I am on my third set and its all the same. I have resorted to not exceeding 4th gear when I want to hit 100 or so but then the engine starts peaking so I cant go much faster than that. I have started wondering if it was the tranny or my engine or something... Please keep this thread going I would love to know what it is!!!
Thread Starter
Registered User
Joined: Jan 2003
Posts: 7
From: Ridgway, PA
vibration
I've had at least two conversations with other 94 Z owners who never were able to resolve the vibration issue. Both wanted to have a lower gear ratio such as 4:10's but the vibration just was too much. One kept the original gearing and the other settled for 3:73's since the vibration would come on only at higher speeds. It's frustrating to me because I want to use this as a "track car" so at various times my speed may get to as high as 125mph. At that speed I'm afraid of losing my filings based upon how much vibration is in the car : )
I'm fortunate to live close to Sam Strano the SCCA Solo II champion. I took my car to Sam's garage last week and he drove it in a fairly heavy rain shower. He said it felt like I turned on the "majic fingers" button at speeds above 65mph. Due to my time constraints, we didn't get the car up on the lift so he didn't get a real good look at anything. However, he felt the problem was potentially from a couple of different issues:
1) The tires on the car are the cheap Goodyear GT II's.
2) Some of the vibration is coming from the exhaust system, which does bump agains the custom S & W Torque Arm which is attached with a bar to the subframe connectors. That portion of the vibration is very easy to distinguish and not a big issue to fix.
3) I replaced the original 3:23's with Richmond 4:10's and they do make a lot of whinning noise in comparison to other vendors. In fact Sam knew they where Richmonds just by the noise within the first two minutes of the ride.
4) He told me to go back to the aluminum driveshaft and he doesn't think the problem is there.
5) The pinion angle needs adjusted to be adjusted and that could definately be contributing to it.
6) I've have too much backlash, although that directly shouldn't cause the vibration.
7) The wrong shims could also contribute to it.
My regular mechanic also called and he had a lenghty conversation with the folks at S & W Race Shop. They indicated that some of the GM front driveshaft yokes were never machined "on center', which was causing vibration problems. Secondly, they prefer aftermarket driveshaft yokes for the pinion rather than GM's.
Anyway, I'm still trying to figure this thing out. Not having owned a Camaro before I thought it was just a problem with mine. What's puzzling to me is that if this is such a persistant problem with many Camaro's, why hasn't a fix hasn't been invented? Heck, I wouldn't have bought the car had I realized it would be this much trouble and potential expense to fix. Maybe I need to go back to just buying Fords again !
take care,
Bud
I'm fortunate to live close to Sam Strano the SCCA Solo II champion. I took my car to Sam's garage last week and he drove it in a fairly heavy rain shower. He said it felt like I turned on the "majic fingers" button at speeds above 65mph. Due to my time constraints, we didn't get the car up on the lift so he didn't get a real good look at anything. However, he felt the problem was potentially from a couple of different issues:
1) The tires on the car are the cheap Goodyear GT II's.
2) Some of the vibration is coming from the exhaust system, which does bump agains the custom S & W Torque Arm which is attached with a bar to the subframe connectors. That portion of the vibration is very easy to distinguish and not a big issue to fix.
3) I replaced the original 3:23's with Richmond 4:10's and they do make a lot of whinning noise in comparison to other vendors. In fact Sam knew they where Richmonds just by the noise within the first two minutes of the ride.
4) He told me to go back to the aluminum driveshaft and he doesn't think the problem is there.
5) The pinion angle needs adjusted to be adjusted and that could definately be contributing to it.
6) I've have too much backlash, although that directly shouldn't cause the vibration.
7) The wrong shims could also contribute to it.
My regular mechanic also called and he had a lenghty conversation with the folks at S & W Race Shop. They indicated that some of the GM front driveshaft yokes were never machined "on center', which was causing vibration problems. Secondly, they prefer aftermarket driveshaft yokes for the pinion rather than GM's.
Anyway, I'm still trying to figure this thing out. Not having owned a Camaro before I thought it was just a problem with mine. What's puzzling to me is that if this is such a persistant problem with many Camaro's, why hasn't a fix hasn't been invented? Heck, I wouldn't have bought the car had I realized it would be this much trouble and potential expense to fix. Maybe I need to go back to just buying Fords again !
take care,
Bud
Registered User
Joined: Mar 2002
Posts: 3,082
From: San Juan PR
It will probably a bad U joint.. ON installation and removal maybe some of the little clips get damaged.. I got this vibration after installing a 4.11... No problem with the diff. maybe the U joint that needs to be replaced.
Registered User
Joined: Aug 2002
Posts: 16
From: tucson, AZ, USA
As stated above, I did replace the U-Joints with the best on the market. They were very hard to replace having been the type that the factory positions with liquid plastic that hardens. Sounds weak but believe me it isn't. I had to put the joint in a vice and then use a torch to heat the caps till it literally exploded them off the joint. Replaced with the metal clip type with a zurk to grease them periodically. This process did nothing for the vibration.