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Driveshaft vibes...

A used 93 Mk.8 driveshaft will run you anywhere from $100 to $200, depending on where you go.

Are you sure that it is your driveshaft giving you the vibrations?


I was experiencing a vibration in the 75 to 80 mph range, and I was convinced that it was my driveshaft. I did four things all at the same time, that eliminated the vibration.

1. Re-balanced all four wheels

2. Indexed the front wheels, so that the valve stem lines up with the yellow stud.

3. Replaced the OEM locking lug nuts with regular style ones.
(Note: These will affect wheel balance)

4. Replaced my strut rod bushings.

Hope this helps.....................
 

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Clarity

One lug nut stud on each of the front hubs is painted yellow. When mounting the wheel on the hub, position the valve stem, so that it is lined up with that stud.

This minimizes vibration caused by the differences in concentricity of the wheel and the hub. It makes the high spot of one, match up with the low spot of the other.
 

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I checked on car-parts.com, I picked one up for $80 including shipping. Don't know if it is common to get them that cheap. It is a 93. I know where I can get one out of a 94 for $60, I know a guy at the yard that has it. My dad has a horror (if you caught the original typing before my edit it was good for a laugh) story about breaking one of the tube in tube shafts like the newer Mark VIII's came with though so I stayed away from it.
 

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The 93 Mk.8 driveshaft is the only year that they made it one-piece.

94's and up are two piece.
 

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Slacks 12 months a year, TCCoAAC Member
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Mark Driveshaft

That is correct,you want the 93 Mark driveshaft.Like was said prior 93 is the only year that I know of for the 1 piece shaft.I am putting a Dennys Driveshaft in my 96 as soon as I take it out of my 93 Mark.Those are like 475 but I think are very light and look so well built.
Chris
 

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phatcat said:
I got mine for $80 + $60 for installation.
What kinda material is the MKVIII driveshaft made of? Also, how long did it take them to install? I was thinking of getting one.
 

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The Mark VIII drive shaft is made....

out of aluminum - not actually as strong as a steel shaft
but considerably less rotating mass which elevates drive
line critical speed and it's resonance frequencies.
Read Chapter 17 of Jerry's thesis - it will clearly
explain everything you need to know about drive shaft choices.

I don't know if it's possible to install without dropping
the gas tank as that's the norm when the tranny is already
in place. It's not super hard to do, but you've got to make
sure your universal joints are referenced correctly when you
install them or you'll end up with more vibration than before.

You REALLY want one, for safety, if you plan on taking
advantage of a removed speed limiter very often.

Good luck with the mods.
 

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Anyone know the part number of the 93 Mark VIII drive shaft?
 

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Also can be done by taking out the rear end...my plan. So, while you are swapping the driveshaft, toss in the aluminum pumpkin with 3.73's! If you do this though keep in mind that you need to talk to Dennis and get a chip to run 3.73's to correct the shift points.
 

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For what it's worth....

according to DanN: Ford (Lincoln) only sells the one
piece design at this time if you buy a new one. When
I won mine the invoice showed a part #F6LY-4602-A.
 
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