1997 lincoln mark viii vibration

[lincolnmark]

I have owned my mark for 2 years now and it has always had this strange vibration a 70 mph and up. The whole car vibrates and at about 90 the car is huming and the rear view mirror is vibrating almost in a circular motion. It has 4 new tires and a brand new steel driveshaft and it still vibrates the same. Hopefully someone has some info that could help me out. Thanks.

 

[Lownslowlsc]

All the signs would normally point to the driveshaft, especially on anything but a 93. What's up with this "new steel driveshaft"?

 

[lincolnmark]

My local drive shaft shop only makes steel it was $300. Installed it today and still vibrates. I love the car by its so hard to deal with the vibration

 

[jbelcourt]

Steel is a step back, for one.

Secondly, yes, vibration like that is almost always drive shaft related. I'm not sure what else would cause high speed vibration.

Have your rear differential checked. Bushings and such.

 

[lincolnmark]

It honestly has some up and down movement on the axle shafts but I thought that was normal for the the push in style half shafts

 

[chris2523]

i also suspect an unbalanced driveshaft or bad u joint.
i suppose there could be an issue with the differential.
or a bent transmission output shaft.

 

[lincolnmark]

How do I check the driveshaft balance...there was weights welded to my new driveshaft

 

[lincolnmark]

Has anyone had any problems with the cv half shafts causing weird vibrations

 

[Right on the Mark]

Does your car have gears in it?

 

[lincolnmark]

The car is all stock

 

[slowmkviii]

I've run into one mark with a bad half shafts 15 years ago.
If you don't do your own work have a shop run it in the air.

 

[driller]

There is a reason these cars have aluminum driveshafts.

The CV joints in the halfshafts may go bad. Usually if there has been any boot damage and subsequent loss of lubrication since they are sealed units.

 

[jbelcourt]

There is a reason these cars have aluminum driveshafts.

The CV joints in the halfshafts may go bad. Usually if there has been any boot damage and subsequent loss of lubrication since they are sealed units.

Out of curiosity, what would you use to lubricate that? I know it's sealed but I tore a tiny jolt in mine doing the real diff and lost some from it slinging out at speed. I realized it and sealed it with RTV and it hasn't lost any since.

I wouldn't mind poking a small hole and "topping it off" so to speak, just to be safe.

 

[driller]

If I recall, I have seen needle injectors for grease applications. I would suggest a high grade lithium grease.

 

[OU812IC]

If you go to Napa they can sell you a single package of the green grease. Get a strap for the boot, they have universal ones or get the direct fit. Cut the old strap off. Slip the boot back. Cut a corner off the package and squeeze it in. Reassemble. Or by the boot kit and be done with it.

 

[rayjohn]

Any chance it could be related to the transmission problem that makes it feel like you are driving on rumble strips in the road. I had that condition at times until I replaced the trans fluid with the recommended type V.