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Strange Vibration; I can't figure it out
Topic Started: Dec 19 2013, 11:42 AM (1,705 Views)
owlafaye
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Dr. Cool
[ *  *  *  * ]
A Deep Thrumming at 52 to 57 mph, in 5th gear only! If you let up or accelerate it goes away...but at a steady 55mph it has a high rate vibration and sounds like a deep humming.
I have ranged through speeds with 4th gear and NOTHING.....Ditto 3rd gear.

This is a 1994 3/5spd. 2dr. sedan...no A.C.

I have insepcted and balanced the front tires and the bearings are OK. Car has 120,000 miles on it. Oil is OK in tranny and I added a little graphite. Engine sounds like a sewing machine and has great power and high mileage economy. Steering is normal lock to lock.

owlafaye@yahoo.com
Edited by owlafaye, Dec 19 2013, 11:47 AM.
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Old Man


:dunno Not sure. What you describe sounds like it's coming from the 5th gear setup. Did it just start? Any repairs done recently in that area?. Do you hear it the same going uphill, downhill, level ground, barrier alongside or not?

Easiest check might be to pull the black "top hat" and look around. I don't think you even have to drain the tranny for that.
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Memphis metro


Jack up the front end of the car, put it in fifth gear and accelerate. Notice the front of the car shaking badly? How do the cv axles look?
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Silver2K


I have a 2000 4/5. I had the same symptoms 2 years ago. Loud hum/whining in 5th gear when cruising at 65mph. If I changed speeds, load, or gears the hum went away. I also had a growling when the transmission was cold when idling. From research on internet, conlcuded I had bad transmission bearings. So I removed the transmission, changed bearings, noise went away. One set of bearings had some minor scratches, so I assume that was making the noise. I think I could have kept driving the old bearings for some years. I must say I have had the transmission bearings replaced 3 times in 11 years. Each time the noise started shortly after I changed the oil and put in a 90 weight gear oil. I hear other people say they use 90w in their transmissions. But I 'll never do it again. I'll stick to Synchromesh. I have read the newer transmissions have different oil guides, so maybe the older transmissions can handle thicker oil. When the noise started, I found I could change the noise by changing the oil viscosity. Thicker oil increased growl at idle, decreased hum at cruise. THinner oil decreased growl, increased hum. Good Luck.
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owlafaye
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Dr. Cool
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Big Rhino
Dec 19 2013, 12:15 PM
Jack up the front end of the car, put it in fifth gear and accelerate. Notice the front of the car shaking badly? How do the cv axles look?
@BigRhino & others;

Good advice...as to oil, I agree, Synchromesh is best. It is not in the transmission I don't think.

New Development: I went 65 mph this morning, not my usual...and lo and behold it started galloping! NO CRAP. aH-hA-rUMPH Ah Ha Rumph, Ah Ha Rumph....loud, whole front of car shaking badly. So I sped up and it got violent.

Now remember, I didn't go 65mph in 4th or 5th previously...so now I believe it is not the transmission at all...the tranny has been smooth as silk for years and years.

CV Axles? What say you? Speak oh people of the forum...thanks

P.S. I had a bad speed vibration up front years back...if I exceeded 60 it started shaking slightly...it also galloped when I put the brakes on....so I changed the rotors and it subsided mostly but not over 70. Over 70 it came back, albeit not as bad. Well I drive 55-60 so I said to hell with it.
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davegran
Old Fart w/Wrenches

owlafaye
Dec 19 2013, 04:55 PM
New Development: I went 65 mph this morning, not my usual...and lo and behold it started galloping! NO CRAP. aH-hA-rUMPH Ah Ha Rumph, Ah Ha Rumph....loud, whole front of car shaking badly. So I sped up and it got violent.
Sounds like what we used to call a "tank-slapper", where the front wheels oscillate left and right at a high rate. Caused by too much slack somewhere in your steering. You should be feeling it in the steering wheel if that's it. It is a very unsafe condition.
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owlafaye
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Dr. Cool
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Thanks Dave,

No, the steering is smooth, steady and no slack. I think CV axles is the answer. I am going to jack it up and run it in 5th gear like BigRhino advises. $205 total at Auto Zone...both axles...good investment. This car has cost me 14 cents/mile since I bought it...cost, repairs, gas etc. Lots more left at less than 10 cents a mile.
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Memphis metro


GeoGlenn just put in some cv axles he got online somewhere. You might check with him and see where and it could save you some money if indeed you end up replacing them. I would drive it rather easy if I were you until you locate the source and repair it. Your liable to sling it out and do some big time damage.
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owlafaye
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Dr. Cool
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Internet search yields remanufactured units (CV axle) for $10 cheaper than brand new from Auto Zone and other Parts stores. Hardly worth it. Remember, you can get brand new rotors from Auto Zone for $15...I have limited my speed to 50 mph until spring when weather will permit me to change out the axles...I plan on new wheel bearings also.
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myredvert
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myredvert

Big Rhino
 
GeoGlenn just put in some cv axles he got online somewhere. You might check with him and see where and it could save you some money...
Great advice. Don't underestimate Glenn's "part-sourcing" knowledge. It's possible he may have a source that is "worth it." Certainly can't hurt to ask...

Big Rhino
 
I would drive it rather easy if I were you until you locate the source and repair it. Your liable to sling it out and do some big time damage....
Best advice you will ever get!
owlafaye
 
I went 65 mph this morning, not my usual...and lo and behold it started galloping! NO CRAP. aH-hA-rUMPH Ah Ha Rumph, Ah Ha Rumph....loud, whole front of car shaking badly. So I sped up and it got violent.
You know the story where the guy tells the doctor "when I do this, it hurts..." and the doctor tells him to "stop doing it!"

After 20+ years of flight testing experimental aircraft, when I read things like this I cringe more than a little. Granted these aren't aircraft, but a catastrophic failure in any vehicle can still be, well, catastrophic. Driving faster than "usual" with a known, but as of yet unidentified mechanical problem that has already been known to affect steering and handling in a negative way isn't inviting disaster, it's more like going to it's house, kidnapping it at gunpoint and demanding it comes with you! Although it can be frustrating to not be able to easily track a mechanical problem down, some problems are not well suited to just let it (or make it!) break in order to find out what the problem actually was, and this seems like one of them.

Please be careful... When a mechanical malfunction is already to the point of manifesting itself in such a major way, it can also be negatively affecting other components (or itself) in ways that can then cause the problem to show up again under different conditions (speed, loading, road conditions, etc.) Don't assume that because it didn't happen until "x" speed previously it won't happen sooner. Unless you have absolute knowledge that "slowing down" will cause a total failure of the system, it's an infinitely better option to take than speeding up. If it were me, I would limit my speed to something well under the lowest previous "trigger speed" and have the discipline to respect that limitation. Not too many people have ever actually known "the big one" was coming before it actually happened. Hurting yourself or someone else, and losing your car in the process isn't worth it!

I do apologize for not being more helpful in assisting you to identify your actual problem, but there are a lot of people on here with much more Metro and general automotive knowledge and experience than I could ever hope to have. My experience is in how to carefully operate with and/or identify known or unknown mechanical problems when the consequences are serious, so please just consider this nothing more than my .02 cents worth!
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Potter
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Col. Potter

dose it go away at 55mph when you clutch in?
in 4th gear on a hill at 55 dose it do it?

to me it sounds like early stages of cv shaft wear.

jack it up on stands, put it in 5th. and let it free wheel if it is in the trans it 'should' do somethig odd
next have a helper sit in the car and have them turn the steering wheel while you safely listen. if their are any clicking or other wear related sounds while the wheel is turning its is probably your cv half shafts.

stop the engine, allow the steering lock to engage, then test for play. shake the tire hands in the 9 and 3 position chack for any give play that would relate to the steering tie rod joint wear. then do the same check at 12 and 6, then spin the tire listening for a grind sound... this checks wheel bearings.

finaly take a long bar and place it as a lever between the ground and tire. have a helper lift the bar and inspect for abnormal movement on the lower ball joints.

i put the last few in their as a normal shakedown... when i was looking for my shake (ended up being the cv shafts) i descovered my ball joints had started to fail as well.
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Nappers
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Sorry for Hijack!

My car does this similar thing. Runs good, synchromesh, fluids good.

At 55-65mph, the shifter vibrates and makes a racket. I can feel vibration on the shifter and on the clutch pedal. Steering is smooth as butter. Axles "look" good, no tears, no leaks. 248,000+ on car, no idea if the CV's were replaced or not. This is in 5th gear. Other gears it doesn't do it.

When I accelerate to a frog hair pass 65, it's smooth as a baby's butt, no vibration, no racket from shifter.

From the posts, CV axles? I thought maybe a flywheel out of balance. Just got new tires and they are balanced good.

Clutch feels good other than that, no slipping. Car runs fine, will go as fast as I want. Just the vibration between 55-65 in fifth gear.

Thanks

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t3ragtop
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Turbo3 and Twincam Tweaker

nappers, your deal sounds like bad motor mounts. the part where you say that you feel it in the shifter indicates the power unit is sending vibration through the rods. the clutch pedal vibration may be from vibration in the firewall.
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Nappers
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Sounds good to me. I will check them out. Will look for tears, loose bolts etc.

Thanks!

Again, sorry for hijack. I did search in the search and google! Didn't want a repeat on a topic.
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