Stock driveshaft rebalance

[Papabear]

Has anyone tried to have the stock Marauder driveshaft rebalanced? Seems to me that this would be a good alternative to replacing it with an aftermarket unit. Just curious to see if anyone has tried it.

[Zack]

There are no problems with the balance of the shaft. The material it is made of can only withstand a certain load. The threshold of a rubber bands stretch is the same principle that applies to the driveshaft.

[BillyGman]

thinking about doing before I spent the $500 on the after market shaft. But I gave in and bought it anyway. But I still think that it might be a possibility. I say that because I've talked to both Denny's driveshaft, and Dynotech which are the only two companies that I know of that make the metal martix shaft for Marauders, and they both told me that they balance these sgafts at a much higher RPM than the stock ones are balanced at. dynotech told me 5000RPM. So I do think that it's atleast in part a balancing issue. I don't know that for sure, however I don't know if anyone here does unless they've tried to have a high speed balance done on their stock driveshaft. And I've never read anyone's statements on here claiming that they have tried that.

[looking97233]

Billy the ballance is not the issue here, the rigidity of the stock shaft is. Think of a jump rope, or any piece of rope for that matter, hold in both hands, pull tight, spin around, the rope deflects in the middle. Same with the stock shaft. when spinning fast enough to do this, it becomes out of ballance and THEN starts the vibration/ harmonics stuff.

[BillyGman]

logic before, and maybe it's true, but unless any one of us tries to have the stock shaft undergo a high speed balance, then all of us are simply parroting someone else(myself included). If what you're saying is the ONLY issue, then why would there be any need for the aftermarket shafts to be balanced at a much higher RPM than the stock ones are?????? if it's merely a matter of the material used, then that wouldn't have to be done. Right????

[Papabear]

I don't think it is a material issue. The stock driveshaft looks to be a pretty nice aluminum one. I have run aluminum driveshafts in all of my SVT products my 99 Cobra was supercharged putting down 450 RWHP and it's shaft had no vibrations. And my 2000 Lightning also had a aluminum driveshaft with no problems. And the truck is probably a little heaver than the Marauder. I think it is worth a shot before going to a aftermarket driveshaft. I am going to see how much it would cost around here to have it done. I would expect it to be pretty reasonable.

[BillyGman]

that it's worth a shot. But so you know both sides of the story here, let me say that the claim is that the aftermarket shaft is a material called "Metal Matrix" which is allegedly a type of Aluminum that's unlike oridinary aluminum since it's mixed w/some type of Alloy to make it harder than plain Aluminum. But weather that's merely a sales pitch by the two manufactures that make these shafts for our cars or not, i don't know. i really can't say. if you decide to give the rebalancing a try, just make sure you go to a place that can balance it at 5000RPM because that's the minimum of what you'll need I believe. And not any place can do that. Let us know how it works out.

[mungce]

O.K., I will admit it, I don't know if my drive shaft is out of balance or not ! I don't hear/feel anything at whatever speed, so you all tell me what I'm supposed to be looking for.............

Jim Williams
Ft.Worth, Tx

[2003 MIB]

Hi Jim,
I've heard it- It's an audible hum (growl) and vibration you can feel in your bones- mine does it at 120mph- it's enough to make you slow down.

[BillyGman]

But it usually doesn't happen unless you install the 4.10 gears since in that case your driveshaft will be turning faster at any given speed than it does w/the stock 3.55 gears. I installed 4.56 gears in my MM, and it was doing that at 90MPH, and now that I have the after market shaft, it no longer does that at 90MPH, but it does do that at 120MPH. But I never go faster than 120MPH anyway, and even that's rare. I'd rather have the 0-60 acceleration.

[Warpath]

Rebalancing the shaft is only a small part of the fix. The real advantage of aluminum and carbon fiber drive shafts is the increased natural frequency of the shaft. Natural frequency is proportional to its stiffness divided by its mass (actually the square root of it). Anyway, an aluminum shaft can be made just as stiff as a steel one but at a lower weight. Therefore, the natural frequency is increased and your top speed is increased. This is a simplified overview of everything.

[vegasmarauder]

Ok, Now for more fuel on the subject...
When I bought my car last Feburary, I heard about the driveshaft being the limiting factor in the top speed. I located a N.O.S. (New Old Stock) MMC (Metal Matrix Composite) Ford Crown Vic Police Interceptor driveshaft that was used in the CV from 1999-2000. It is out of production now and no longer available from Ford. I weighed it before putting it in and it weighs 16 lbs, compared to 19 lbs for the stock MM driveshaft. This MMC shaft was what Steve Babcock said was spec'd for the MM when the top speed was to be near 140 MPH. I wonder if this shaft would be an acceptable alternative to the new MMC shafts?

[RCSignals]

I think that AMMC shaft that was used on some CVPIs is still available as a service part.
Also, since 3.55"1 rear ratios are available again for the '04 CVPI, the AMMX shaft may be used with it too.

[vegasmarauder]

When I had my parts guy run the old number it was superceded to a 04 CVPI number. When that shaft came in it's just an aluminum shaft with the same markings as the 01 up PI shaft. It dosen't have the "MMC" marking on it either. It just says "POLICE". He checked the old number and it is discontinued, with the 04 number as the "new" number. We got an old number shaft and put them side by side and they are different. This goes with what was said at Ennis about the shafts being discontinued for use in the 2003 MM. If you have a dealer parts guy seach for only the old number you will get what's left in stock at Ford dealer parts departments. Last time we checked about 3 weeks ago, there was only about 20 spread out all over the US.

[RCSignals]

I would think that the '04CVPIs using the optional 3.55 gear set would get a MMX shaft as they did in '99, '00. Interesting

[joflewbyu2]

N.O.S. (New Old Stock) MMC (Metal Matrix Composite) Ford Crown Vic Police Interceptor driveshaft that was used in the CV from 1999-2000 --- What was/is the price of this shaft ? are there any out there ? who makes them ? is it better/comparable to the DYNOTECH ?