Pulsing Vibration above 70 MPH

[Ozz]

I searched for my condition and I didn't find anything that was the same.

I have a pulsating vibration above 70 mph. It's strange in that it starts in the front of the car. I can just barely feel it but I can see my hood vibrating, then it hits me in the seat and then it moves to the back of the car and dies for an instant, only to start again in the front. The cycle only takes about 2 seconds.
I think I can hear it as well as feel it so I know as it moves from front to back...

Any idea what this could be? This has been going on for a long time - doesn't seem to be tire dependent or brake dependent (redid all 4 brakes recently w/ turned rotors - now as smooth as a baby's butt and I put on a different set of wheels/tires in the winter with no effect on the vibration).

Not sure if this could be related but I also am searching for a poping noise in the front end. I replaced the upper control arms, shocks and springs. I ruled out the sway bar/linkage by unhooking it and going for a spin. I'm thinking that problem is must be in the lower control arm. Could this be causing this very strange condition?

I am leaning toward U joints or the driveshaft itself but am hoping someone else has had this experience and can shed some light on my problem. If it's the u-joints, are they pressed or clipped in?

Thanks.

[Blackened300a]

You do anything to the exhaust? I have the same resonation you are talking about and I noticed it to be RPM related instead of speed. Around 2200 it comes in and it's annoying. With my 4.10s the sound comes in at 40mph and then again at 65 mph both times it's at 2200 rpms. If I drive at 70+ mph I don't hear it or feel it.

[Vortech347]

It can also be the wheel bearing.

[martyo]

I am leaning toward U joints or the driveshaft itself but am hoping someone else has had this experience and can shed some light on my problem. If it's the u-joints, are they pressed or clipped in?


Take it to a decent drive shaft shop and let them look it over.

Although it is hard to diagnose these issues over the 'net, it sounds like a harmonics issue from the drive shaft.

[Ozz]

Blackened,
No, no exhaust mods, stock rear gear. No drone or anything at any rpm.

Vortech,
Front or rear wheel bearing or could it be any. I've had one of the front hubs changed - although several years ago.
Front hubs seem pretty tight when I jack up the car and try to tilt the wheels top and bottom.

martyo,
You're on the same track as I am. Now I have to find a 'driveshaft shop'. Seriously, would I look under 'drive shaft' in the yellow pages or what? Would I take in just the drive shaft or the whole car? I'll do a google search and see what comes up...

THANKS!

[Vortech347]

Okay, its not a hub then. On a recent trip with my wife's Cobra this year every time we broke 90mph it would have a vibration in the front. I had just barely had the wheels/tires road forced. Once we got to our destination in MT I jacked up the front of the car to check everything. Sure enough one of the wheels had an ass hair of movement. I can't believe it but in a town of only 3 parts stores one of them had a mustang hub! Fixed the problem. Thing that boggled me was there was no noise. Just vibration.

[martyo]

martyo,
You're on the same track as I am. Now I have to find a 'driveshaft shop'. Seriously, would I look under 'drive shaft' in the yellow pages or what? Would I take in just the drive shaft or the whole car? I'll do a google search and see what comes up...

THANKS!

Try to find a shop that can take the whole car in.

If not make sure you index the shaft so it goes back in the same way it came out.

And, if I recall correctly, you will need 12 point sockets to remove it.


By the way, how far is Plymouth from Troy?

[martyo]

http://www.google.com/#hl=en&sugexp=ppwe&cp=37&gs_id=32&xhr=t&q=drive+shaft+service+plymouth +michigan&pf=p&sclient=psy-ab&site=&source=hp&pbx=1&oq=drive+shaft+service+plymout h+michigan&aq=f&aqi=&aql=&gs_sm=&gs_upl=&bav=on.2,or.r_gc.r_pw.,cf.osb&fp=5117386cc9c78ce3&biw=1024&bih=650

[Vortech347]

12 point 12mm wrench doubled up works nicely. Remember when reinstalling, they need 75-90ft=lbs of torque and lock tite.

[Ozz]

Thanks for all the info!

Plymouth is ~20-25 miles from Troy. I work at Ford in Dearborn so I'd like to try to find a place somewhere between home and work. I contacted a place in Farmington (5 miles) that looks promising.

[martyo]

Thanks for all the info!

Plymouth is ~20-25 miles from Troy. I work at Ford in Dearborn so I'd like to try to find a place somewhere between home and work. I contacted a place in Farmington (5 miles) that looks promising.

Cool, keep us posted.

[Ozz]

Just to update this thread - I have been chasing a 'pop' in the front end so I changed the lower control arms, and put my winter tires/wheels on the car. After that I can do 90 on the highway without so much as a shimmy... So either the worn out lower ball joints were causing my vibration or the summer tires (nearly worn out) were. I'll know for sure in the spring when the summer tires go back on.
Glad it's not the driveshaft....