blue birdy 87

Title pretty much says it all. I have had this problem for a while and i figured it was mostly due to my over-worn tires. Just the other day i got a new set of tires and alignment. It helped slightly but the car still shakes the dash pretty hard. It feel like it shakes up and down. Any help is appreciated

Edwardgp

Usually when they do an alignment they well not proceed if something is wore out in the steering department. Have you looked at your wheels really closely?

8t2 z-chev

Yeah,check the wheels(are they OEM GM?)bent rear axle
could be a cause too-have a friend follow and look for
wobble or jack up rear of car with wheels free to turn
and look for wobble.

two-if-by-sea

iTrader: (22)

My first Camaro, 20+ years ago, would shake so uncontrollably, that I would have to stop the car. It didn't happen alot, but would happen at least once per week, always when I was driving at highway speeds. I got new tires, and the shakes went away forever.

Stevolwevol

iTrader: (1)

I had the same problem w/ my IROC, and it was a bent axle. I found one in a bone yard, and the problem was solved. The previous may have hit a curb good and hard.

robg91z

iTrader: (1)

Ur tires probably need a balance or could have a bent rim. Try looking for anything look on ur suspension. Do u feel the vibration on the steering wheel? On ur seat? Or both?

Stevolwevol

iTrader: (1)

Yeah a bent axle is just one of a number of possibilities. Old tires could cause vibrations also. Rubber can get hard, and flat spots can develop. The vibration you are describing sounds a little more substantial though. Does it sway at slow speeds?

blue birdy 87

There brand new tires all way round and alignment. No sway at lower speeds. To me it feels like the front end is going up and down, not the back so I dont think its an axle.
I looked at the wheels and as far as I can see its perfect round

Could it mabye be bad motor mount?

Coyote850

iTrader: (1)

I had a problem with my truck shaking after driving it about 20 minutes. It was the parking break causing drag and heating up the rim. When it happens, is there any unusual smell?
Could also be missing on a cylinder causing vibration. Motor mount is a possibility.

blue birdy 87

Nope no funny smell or missing. Motor smokes on startup but the lg4 runs strong.

Now I also noticed from a dead stop if I gas it good and have a good launch theres a thud in my centerconsle area. One fairly noticable thud.

How do I check if I have a bad motor mount?

JamesC

iTrader: (5)

Transmission mount issue.

JamesC

Capt. P

iTrader: (1)

Also check U- joints, could cause that also.

Stevolwevol

iTrader: (1)

I would bet a weeks pay you have a broken tranny mount. That's no bit deal. However, it shouldn't cause the shaking you described.

rough

Broken trans mount does nothing but hold the trans from jerkup up/side to side/ and slamming the tunnel.

I've had the same shaking issue you have had, for years now, So many parts, $, time invested, and still no fix.

KiLLJ0Y

iTrader: (1)

Could also be a broken torque are mount, those fail more than the tranny mounts, and would jack up and hit the trans tunnel on a launch

florida_gators

iTrader: (2)

Mine did something very similiar just before a fuel injector went out. Replaced just the injector and the problem went away.

Dakota W.

It's either the tranny or torque arm mount, or a bent/unbalanced driveshaft.

DARKmj16

iTrader: (6)

the thumping is a trans mount, if it was a torque arm mount you would hear a thump everytime u hit the gas.

as for the shaking...up and down... for some reason im thinkn bad struts...or a spring issuse, those 2 are bout the only thing i can think of that affects up and down

so to prove its the trans mount for thumping get under your car with a crow bar or even a long screwdriver or pipe, place it between the trans and cross member and push up...see that grap in the rubber?

for the springs jack the car up (not on the a arms) and look at them, outa place? bent broken?

for struts (and the rear shocks) push on the coner of the car really hard a few times then stop, if they are good the car should stop bouncing quickly. then move to the next coner.

Stevolwevol

iTrader: (1)

I had almost non existent struts before I replaced them, and it didn't shake like bluebird is describing.

DARKmj16

iTrader: (6)

maybe a spring problem with bad struts? but the only t hings i can think of that would be affected at highway speeds that shake up and down would be springs and struts...or lettign of the gas and hitting quickly and... hey wait how does the trans shift? maybe it is a trans problem.

for example when i lift off the gas in my car (manual trans tho) the car lowers and kinda does a very very brief little shake, barely noticable but the point is what if the trans is having problems takeing the power from the motor and putting down to the ground?

Darth 93

I had this in mine for years..60- 70 mph was really bad. ....swapped tires, swapped rear axles ,balanced the driveshaft, was stll there. Then I went to an alum driveshft from a 4 th gen. Much different car after that. Not totally gone, but you have to get to shred my licence speed to notice it.
The test for this is a couple ways
1. Re index the driveshaft to the rear axle 180 degrees. Just indo the 4 bolts at the rear u-joint..be carefull with the u joint so the caps don't come off. . Rotate it 180 degrees and re instal. If the vibration gets better or worse ...this is your issue.
2. This is not a long term fix! Add a hose clamp near the front or rear ujoints...one at a time... rotate it around and drive vehicle. See if vibration changes. The heavy part of the clamp changes the balance on the driveshaft.
Either way will help understand if this is your issue. And does not cost much to try.

Stevolwevol

iTrader: (1)

Did you jack up the back and watch the wheels go round and round??? That's how I discovered I had a bent axle. The previous owner drove it long enough that the tire wore unevenly, so I replaced them. They were ready to gro anyway. Try what I said. Use a hydrolic jack on the differential when you do it. Have someone put it in gear and give it throttle. A tire store will do this for you as will a repair garage if you don't have the jack. Logically, something going round and round is not in balance. Bad struts will only unveil and excasorbate the problem, not create it.

ghost91

not to bring this thread up again...but ive got this problem too. from like 80 and up it seems the whole interior shakes. the dash goes pretty good, and a few other things. i am getting new tires soon, but would that be the problem? axle is good, suspension is good, no broken tranny mounts, motor mounts. everything is good. its weird though...i decided to take it out of overdrive, and put it in normal drive and it didnt do it....just cant figure it out.

DARKmj16

iTrader: (6)

uk wut Stevolwevol i think ur rite.

im by no means a master mechinic but i would like to put one thing out, that ghost brought up. everyone so far that says they r having the shaking has an auto trans... while the manual guys dont seem to be having this problem (correct me if im wrong) and the trans obvouisly has round things spinning.

so wut u guys think the OD in the autos going bad...lol after all these years.

Stevolwevol

iTrader: (1)

If it were auto trans related, I would guess the torque converter may be the culprit, only I have never heard of this.

tunerkiller

I have the shakes in mine as well. at the speed of 73 or higher, my car shakes. i already know i need an alignment by the way the tires are worn on the front. the outsides look terrible, so i will have the tires replaced, and maybe a high speed balance. But, and i say BUT, i have a t-5. so, it cant truly be the transmission. it has to be something else. i am taking it in to town to get the whole tire/alignment/balance thing figured out since i have a 14 hour trip ahead in this car. yes, i am that crazy to do a road trip in a 1991 rs Camaro with a 305 and a swapped t5. let yall know what happens

Edwardgp

Could an unbalanced drive line be the problem, maybe a weight on the drive line came loose and flew off somewhere.

evilemokid94

iTrader: (6)

Mine does the same thing. It's around 80mph I believe. It use to do it around 70 but after I took it on the freeway to 75 it smoothed out.

80schild

iTrader: (5)

Mine starts shaking above about 85, but I really can't tell where it's coming from. I know I don't feel it in the steering wheel. I have new inner and outer tie rod ends, new struts and mounts, and new shocks. Tires are about four years old, but very few miles on them. Transmission freshly rebuilt.

The previous owner told me it had a bent axle, but that he had it straightened out at a machine shop. Is that even possible? Seems like I'd feel a wobbling wheel before 85mph.

Stevolwevol

iTrader: (1)

I would bet you still have a bent axle. I had a bent axle on one of my camaros, and the previous owner drove it long enough with it bent that the tire wore unevenly, and I needed to replace them also. You can tell if you jack up the rear, run it in gear, and watch. I did it with mine and it was very apparent. These cars should cruise nicely at 85.

blue birdy 87

How hard would it have to be hit to bend an axle?

Stevolwevol

iTrader: (1)

If you are asking me, I really don't know. My guess is the p o hit a curb or something like that.

80schild

iTrader: (5)

Did you replace the axle shaft or the whole rear end? I just had the bearings in my rear end replaced, so I know I'm not going to replace the whole thing.

80schild

iTrader: (5)

I was told mine "got sideways" on the interstate, and that the wheel hit something. There was no body damage to the car.

Stevolwevol

iTrader: (1)

So you were "pogo sticking", and then hit something?

80schild

iTrader: (5)

Not me, the previous owner. I'm guessing maybe he hydroplaned or something.

Like I said, mine rides smooth as silk until I get to 85 or so. If my axle is still bent its probably just slightly.

tunerkiller

cant be that because when pulling 73 or more, i am pushing close to 1500 rpms, and thats in 5th. at 47 in 4th, i turn the same rpms. there aint no way that it could be the drive shaft.

I believe its my tires. the front two have deteriorated from the inside. the weight on one is so bad, that there is an uncorrectable total of 19 ounces in weight on just one tire. JUST ONE! i doubled checked the work. so i know what they are talking about. it gets weirder. I bought four tires, two matching and two not matching, when i first got the car from a cheap store, well the front had more tread on them when i bought them. now they have less tread then the rear. the front are almost bald. its like a front wheel drive car! like i am doing burnouts with the front two. the rear, have perfect tread, but i have spun those tires so much that they should be bald. i have not rotated them either. completely weird.

DARKmj16

iTrader: (6)

lol our cars are in deed weird, well i use to hav an auto but swapped to a t5. i dont get any shakes at all (except for the usally rocking n rolling the older cars get at high speeds, weather it be from the road or wind or w/e) BUT when i got my 92 camaro the po of the po stripped it and was using it for drag racing wit out fixing the suspension, so needless to say i rebuilt the whole front end... im talking new center link, inner and outer tie rods, ball joints, rotors, calibers, idler arm, struts.

hmm would a wrapped rotor cause it? or maybe its something else im not sure.

tunerkiller

i dont know man. really, i am more concerned with the oil leak right now. it is scarin the **** out of me.

DARKmj16

iTrader: (6)

lmao im leaking oil to, from the rear (its my intake) but the odd thing is... i never lose oil weird

tunerkiller

Overflow? mine leaks on the passenger side, drips down onto the t5 bellhousing, then flys back on to the catalytic converter and starts to burn.

DARKmj16

iTrader: (6)

no nvr overfilled or under filled its weird. and my oil leaks from the intake where its "sealed" (with rv sealent) to the block... no big deal i dont lose oil, dont smell it burning, just covers the underside of my car...lol yet again oddly enough not the trans, well the top or sides anywaz? but anywaz lets not get off subject

tunerkiller

right. i tend to get off topic, just about all the time. the vibration thing, should be better by tonight though.

tunerkiller

replaced all for tires, got it up to problem speed, and it rode smooth, all the way to 100 mph

Stevolwevol

iTrader: (1)

It felt good didn't it?

tunerkiller

Hell and yes. hate spending over half a grand on tires, but oh its gonna be a much smoother ride. now if i can get fifth gear from popping out.

Stevolwevol

iTrader: (1)

I replaced tires on both of mine. I got ricon raptors z rated for the RS, and firestone Indy" for the Iroc. I wasn't after z's but they were on sale. Good for cornering, and high speed of course. They set me back just shy of a grand. third gens love 100. What tires did you get?

tunerkiller

Cooper Cobras. not exactly what i wanted, but the cheapest i could afford. i am not really gonna be pulling any crazy stunts at the moment, so, i really dont care about the brand of tires. as long as they do their job, i am happy with them. in about six years, ask me again what i have on there. it may be a ten or nine second car on the crowed streets pulling some wicked speeds on tight turns.

vwdave

My brother overheated the front calipers on mine so badly that the car developed a horrible vibration. Anyways, mine is smooth till 130 or so.

Anyways, I can pull guesses out of my butt, but dont blame me if theyre crappy guesses. The only person that can find the vibrations is either you, or a competent mechanic. Another idea is to put the car on a raised dyno and have the operator run the car and see if a vibration is noticeable. Trust me, it is physically visible most of the time.

You need to determine if its RPM related, or vehicle speed related. Despite what was said earlier in the thread, driveshaft speed is increased along with vehicle speed. Here is a list of some possibilities.

Imbalanced torque converter, bad output shaft bearing, U-joints, bent or misbalanced driveshaft, worn pinion bearing, belt axle, bad wheel bearings, worn shocks, rims/tires being screwed up or misbalanced.

Hope that helps.

Crasher0083

Glad you said wheel bearings. Thats what made mine shake over 80mph!!!