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Discussion Starter #1
This car will shake side to side extremely bad at 25-35 mph. It feels like if I keep it at this speed it will rip apart from side to side. As I go faster the vibration gets faster and less violent but still there, I know this is a major problem and I do not want to drive the old girl until I figure out what causes this and replacing the messed up part(s). Lugs are tight on the rims, Car does not have alot of play in the steering wheel. The violent shake and vibration is only there when accelerating, not when coasting or turning...thats the hard part I am having to figure this out. Well as long as I dont have to use the gas its a real smooth ride..LOL

The only guess that I have is the steering rack, back in September I brought it to Sears and the mechanic would not do an alignment for me until I replace the rack. Any one with any more ideas would be highly appreciated. :hmm:
 

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1992 Town Car Cartier & 2014 Accord LX MTX
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When you said it's only during acceleration, it makes me think that it's something with the motor, maybe you have a dead cylinder or something... :hmm:
 

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White Diamond '03 DHS (with DTS floor shift)
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Very odd that it is only under acceleration. My first thought was a tire cord seperation. I would still check that.
 

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94 Fleetwood Brougham
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Have someone run along side of you while driving, and watch and listen. A lot can be learned that way
 

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rule out the engine by revving the engine in park or neutral and see if it still shakes if it doesnt then its the drivetrain

to check the drivetrain jack up the front of the car and run it to see if any of the parts are loose

I'm thinking something is really loose and about to fall off so DONT drive it anymore until you fix it and I doubt it could be the steering rack

Most likely its the motor itself if it is shaking really bad I've seen similar problems when spark plugs are not gapped properly OR if 1 of your coil packs is dead 2 of your cylinders won't fire causing a shakey feel.
 

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Discussion Starter #6
Hello guys, thanks for the fast replies, I would have to rule out the tires because it is only under acceleration. As for the motor, this motor purs like a kitten and revs up beautiful, nice and strong with no error codes as well. I did get a hold of the throttle under the hood and gave it a couple of good revs and no major movement from the motor mounts, so the motor and tranny are tight. The wheel bearings are new, one this summer and one last year. No noises or play from those either.
I did have it jacked up late one night and quickly kicked the tires and put it in gear but i did not notice any odd vibrations when up with no load on the drivetrain and then it started snowing so I took the car back down and havent done anything else with it yet except taking it the other day for a shaky ride to the post office and back.
Tie rod(s)/ball joint(s) maybe?
I would think that when accelerating, the tires have a load towards the rear of the vehicle so there is stress on the tie rods and rack. but thats just my guess. Agreed, Yes this thing is dangerous and I am taking a gamble with my life and others driving this down the road until it is fixed. This vibration is more of a side to side motion so I am very confused.:banghead:
 

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Check motor mounts. The front trans mount is common to fail.

does it do it in reverse?
 

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Discussion Starter #8 (Edited)
When I first got this car the last motor and tranny that was in there had both the front mounts broken and the whole engine would lift up and the doughnut gasket would blow exaust out through the pipe when I floored it...so that cant be it....because when I put in the new to me, and half the milage motor and tranny I checked those out before I installed it. I have checked the mounts and are in good shape on this motor and tranny.

As for going in reverse, it backs up the driveway fine. I dont think I can go fast enough in reverse for it to do anything. I would have to go at least 20 mph to see if it would start to shake, I think, as the shake and vibration in a forward gear will not happen under 20mph. 30-35mph is the speed when the car really feels like it is going to shake side to side so violently that it feels like if I hold that speed the car will fall apart...possibly ripping the front end apart. But as I go faster the vibration will get faster and less violent.

So something spinning maybe axle shaft bent.....But that would be a constant vibration even not under acceleration....As soon as I let off the gas...no matter what speed I am going the vibration does go away and it is smooth. I hope this helps everyone out trying to help my poor car and my frustration as well
 

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Discussion Starter #9
Maybe upper ball joints?? I will have to jack this up again soon and check this out a little closer with more time to narrow this down. No garage or pavement here just a mudded up driveway after the snow melt to work on it. The weather, My driveway and my time available to diagnose have to all work together to take a closer look at this.

BTW this started happening after I did give it some good throttle taking off at a set of lights on a short trip. Maybe whatever was failing really didnt like it after that and finally broke or is really close to snapping
 

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Im starting to think it may be something in the rear maybe bad bearings or something similar in the rear wheels.

lift up the rear and spin the tires


If you jacked the car up and ran it well about 35 mph and you got no vibration then its not the front end
 

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Look closely at the springs in the struts. Also check the strut bolts on the top 3 13mm and 1 BIG nut. Make sure all are there and tight.

Check the lower ball joints for something up. Jack up car and watch them to see if they move. Bout all I can think of.

Maybe axle to spindle nut?
 

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if its a spindle nut you can also just check the axles for too much movement when the wheels are spinning you need one person to press on the gas while u look under it
 

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Discussion Starter #13
Thank you guys for all the great ideas,

I will check out all of those things real soon here, its getting close to that great holiday, and I dont know when I will have the time until after then....Maybe I will try to give myself an early Christmas present and work on the caddy this week. I will let you all know what I come up with when I can get some time get out the plywood and jack.

I did have to remove the 2 large bolts on the struts that attach to the spindles when I changed out the motor and tranny, I thought I tightened those up real tight so I didnt mess up the alignment, they might have loosened up. I will check the axel nuts as well, because I was there too.I will also check those top strut bolts, and the rear wheel bearings and stut bolts as well.

Again thanks for all the things to check out and if any more ideas come to mind feel free to let me know.
Russ
 

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Right tight is like 150+ ft/lbs, right? They need to be TIGHT. But you likely would see the wheels lean at an angle if it is off.
 

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spindle nuts do have to be tightened a lot the best way actually for me has always been to make a mental note of how much thread there is on the spindle

Also I use an 18" breaker bar to tighten the spindle nut or i use an 18" ratchet.

I highly recommend using A NEW spindle nut as per the manual they are only about $3.00 at autozone and they are in stock.
 

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Spindle nut?! I did a wheel bearing replacement(front) on a 92 GMC Safari (RWD) & it said tighten till you cant turn in any more, then back it off a 1/4 turn, the insert cotter pin!?, Do you mean because its FWD & the CV assembly holds the wheel bearing together? Or the rear spindle? because I couldn't see the rear being 150lbs.
 

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Discussion Starter #17
Well iknow its been along time since I brought this problem to this website. This week I am hoping to fix this issue with my caddy. I had some time to look at my car and I have done the following:

Replaced rack and pinion assy, Including all tie rods and ends,And I Replaced drivers side CV axle with still no fixing my SHAKE.

Today I am getting in the passenger side axle from autozone online. When I took out the passenger side CV It was bad, So that should rectify my SHAKING problem here after I replace the front 2 motor mounts are now broken.

So when I gave the car gas at 20+ MPH, the motor was able to twist side to side as well as up and down From the bad CV. So also new front motor mounts are on their way as well..Fun Fun Fun.

it's funny that the motor mounts were fine way back when I started this thred....so I am thinking that the bad CV fibrated so bad that it made the motor mounts separate as well? I dont know..I do know that they are bad now and will be new this weekend or so.:bigroll:
 

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Since the motor was shaking that violently, it doesn't surprise me that another set of motor mounts went bad. Way to be persistent in looking for the problem! I hope that driveshaft is it. They sure do drive nice when they're right. :)
 

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Discussion Starter #19
SkarTisu said:
Since the motor was shaking that violently, it doesn't surprise me that another set of motor mounts went bad. Way to be persistent in looking for the problem! I hope that driveshaft is it. They sure do drive nice when they're right. :)
Ended up being the passenger side axle after all...took it for a drive today after the install and no more shake!!!!! I will replace the mounts as soon as they come in,But all I can Say Right Now Is, WOOO WHOOOO!!! :golden: The Shake Is Gone!!!!
 
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