Scott_92RS

I have changed just about every suspension component on my car within the last year. I have put new Shocks/Struts, Jamex lowering springs, Moog ball joints, idler arm, pitman arm, and centerlink, IROC 36mm/24mm swaybars with poly bushings and endlinks, IROC wonderbar, BMR LCA relocation brackets, Poly/poly Tubular LCA's, and a Poly/poly Tubular Panhard bar. I have tried switching wheels with my sis's 91 Z, no luck. I had my dad watch the engine as I tapped on the gas while in gear, engine mounts look fine. I have replaced the Front Rotors and pads, and rear shoes. I did a test to see if the Torque Converter was bad (got up to about 80 mph when the vibration is extremely bad, and put it in neutral). The car vibrated all the way down to about 65, then got a little bit better, the engine was at idle before 65, so the Torque Converter seems to be OK. There are only 2 things that I have not checked: Tranny mount, rear axle. I dont think the tranny mount is bad, because I had the vibration even after I got my new tranny in about a year ago. This leaves the rear axle. Is there anything else this could possibly be from? I can feel the vibration just a little all the way up to 70, but as soon as I hit 70, the interior starts shaking and going nuts. If you have any suggetions, please let me know. Thanks.

82camaro

A bad torque converter will sometimes vibrate in neutral with the car not moving if the rpm is held up. Try revving the car while not moveing to verify it's not the engine/torque converter. If it only does it at speed, look at the stuff that is rotating. Out of balance driveshaft, bent driveshaft, froze u-joints, worn out u-joints, axle/pinion/carrier/wheel bearings, warped drum/rotor.
I hope you didn't replace all those suspension parts and stuff to fix a vibration problem. All of those parts won't cause a vibration--they may make it worse if they are worn out though.

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350 with stealth intake, holley carb, 470 lift cam. 700r4 with .5 boost valve, vette servo, tci lock-up kit, B&M megashifter. Richmond 3.73 gears, powertrax locker, timkin bearings, synthetic lube. Custom 3 inch single into 2 2.5 pipes. 1 1/2 drop springs, 1 5/16 solid front sway bar, 1 inch rear bar, custom subframe connectors, custom LCA relocation brackets. Kobel ground FX, current red metallic paint. Lots of other stuff...
82camaro

nicmike85

Balancing the drive shaft and wheels are speed spacific. This means if you balance them for high speed they will vibrate at low speed or vise-versa. The driveshafts in our cars are notorious for having an 80mph death wobble. I would try having it balanced at a high speed. Your wheel bearings can do this also as they will loosen up with wear.

Scott_92RS

No, I didnt replace some of the suspension stuff to fix the vibration, I just wanted them so the car will be ready when I put a decent engine in it. I forgot to list that I do have a balanced aluminium driveshaft in the car. I am not sure if it was high speed balanced or not, I didnt know there was such a thing. I dont think its the Torque Converter because even when I am at idle and doing 80 (in neutral), I have the vibration, but I dont have any vibration when stopped. I'll check my wheel bearings when I get a chance. Thanks for the help guys.

FiReBReTHa

i have some major vibes too man. and i think that mines in the wheel balancing and the alum drives shaft (on its way) so hopefully all that willl fix it. ill update once i do it..

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Omega

iTrader: (1)

Your axles might be bent. Have you ever hit a curb or any kind of accident? Take the axles out and have them checked. The most common vib is from the driveshaft or wheels, but since you checked those, the axles are my only other answer.

Ed1LE

iTrader: (39)

I had the same problem & it drove me nuts too! Common areas are tire balancing & driveshaft but here's a couple other suggestions. Rear axle bearings or gears. Turned out I broke half a tooth off my ring gear which then caused the vibration b/c it wouldn't match correctly at certain driveline speeds. At 60 & up the car vibrated like crazy. Also, spinning the tires when taking off it would vibrate when the driveline would hit that speed (w/ tires spinning) & then would disappear when I shifted into 2nd. Hope this helps.

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'91 Z28 1LE; 355, Sportsman II heads, Edelbrock TPI w/ 58mm TB, Tremec TKO 5-speed, 3.73's & much, much more

Scott_92RS

It seems to be speed related, not RPM related. I can put the car in neutral and let it idle when the vibration gets really bad, and I still have the vibration. I will be replacing the rear sometime soon, so maybe I will find out then. Thanks guys.

wm_sorg

I have this problem too. I am thinking the U-jonts are too stiff. Had the tires balanced, no diff. Rear shafts appear ok. I also noticed that mine (although speed related) is not consistant. Sometimes I can go 70 no vibes, other times I feel like I am in a paint mixer. If I speed up or slow down it goes away. Then comes back if I resume crusing speed.

Scott_92RS

I've been noticing something else weird, too. It seems that when the car is cold, I feel little vibration all the way up to 50. After I hit the magical 70 mph and the bad vibrations start, my car will vibrate at all speeds above 40 mph, and get worse as the speed increases.

wm_sorg

Sounds like my car. Does the vibration get worse after 70. If i push past 75 the vibration calms down a little.

Scott_92RS

Yes, the vibration gets worse after 70. Could this be cause by bad timing? a long time ago my dad ad I had to take off the intake manifold because of a leak. We think we got the distributer in a tooth off because it wouldnt start at all. We just advanced it till it started up. We had to advance it a lot to make it run right. The problem seems to be worse after the car is warmed up, or the if the outside temp is really high. Could the computer be doing something with the timing that is causing the engine to vibrate?

wm_sorg

Not sure if your problem is engine related. I do not think mine is. Bring your car up to speed and throw it in nuteural. How much of a difference does it make?

My viabration is felt through out the car and seems to be eminating from the rear.

Scott_92RS

Makes no difference if I put it in neutral.

wm_sorg

This indicates that your engine is not to blame. I will be replacing my U-joints soon. If I can find an aluminum drive shaft for a reasonable price I may replace it as well.

Let me know if you do any of the same.

W

Scott_92RS

I recently replaced the driveshaft with an aluminium one. It has new U-Joints and was installed professionally. Didnt change a thing.

[This message has been edited by Scott_92RS (edited August 03, 2001).]

wm_sorg

How much did that run you? Did you check the rear axl shafts. I had an 87 Formula that had bent shafts. Viabrations would get worse with speed. and more consistant.

Take your rear wheels and drums off. Put the car in drive and let it idle. When looking from the rear the axl should not have any side to side motion. When you are finished put the cat in neuteral and shut the engine off. Remember the axl will still spin so you can not put it in park. Remember not to step on the brake or you will have a mess to deal with.

Scott_92RS

I got the driveshaft for $160 shipped, $70 to have balanced and installed. I would like to try what you posted, but I wont feel comfortable doing that in my driveway (too steep). Maybe I can bring it somewher and have them do it. Thanks.

wm_sorg

Did you get it used? If not where can I get one for that price. These vibes are driving me nuts. If I can not resolve with the drive shaft I am at the point of looking for a specialist.

MightyMouse

My car does the same crap. This is my story.
I got some new tires and the vibe went away for several weeks then it came back so I went to discount tire for a balance check. They balanced the tires and it did the same $hit so I jacked up the back end and took off the back tires and drums. It was then that I noticed that one of my axels was a little bent so I forked over 75 dollars for a used one and the vibe did not get better. I lifted the car once more and took off the tires and drums and ran the driveline to 1?? mph and it was smooth so I put the drums and nuts on and did the same thing once more and it was still smooth after that I put the tires back on and the vibration was back. I then proceded to Dis. tire for another rebalance. They told me that the alignment was off(Management BS) but they balanced the tires anyway and the vibe was still present. The tires that I have are 215 5 15 radial hrx made by fisk. While jacking arround with the tires I noticed that they were slightly out of round(all of them). Are these crappy tires that cant handle a few hard corners while mantaning roundness or do all tires suffer perminant internal damage from hard turns? I plan on buying a new set of tires and see what that does, but dam, a new set of tires every couple of thousand miles can get expensive. To me this is $hitty. I love my car but hate to go 70+mph dam crappy. We need to find the cause of this and fix it.

Scott_92RS

Search for JamesC on this board. He sells them regularly for that price. Check the classifieds. They are usually 160-170 shipped.

wm_sorg

I have gone throught this same BS with tires, rotating and balancing. The vibes seem to eiminate from the rear of the car. I do nor feel anything throught the steering wheel. Is this the case for you as well? I love the car as well but the virbations make it real annoyance to drive.

Scott_92RS

Is it possible to have a bent axle and not have the tires look like they are vibrating? I had a friend follow me one day, and he said he couldnt see any part of the wheels shaking or bouncing. Could I possibly have a bent axel near the end of the axle (towards the wheel), that does not show its full vibration until I get up to 50, 60 mph? It sounds like a valid concept to me. Thanks.

Scott_92RS

My friend and I took a look at my car today (he's a mechanic at a local dealership). He noticed that my tranny mount was broken. I replaced it with an Energy Suspension unit, but I still have the same vibrations. Any more ideas? We are going to take a look at my axles on Monday.

mckenzie

Hello, i would see about getting your tires "trued". i work at a dealership, and you wouldn't believe the amount of "out of round" tires. they should be able to let you know if thats the problem with a test drive and maybe taking off a tire and spinning it. best of luck, tom

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86 iroc 305tpi auto. mild cam

Holio

Scott_92RS and wm_sorg, have either of you resolved this problem ?