Alum. Driveshaft Question

[Synned]

Almost like clockwork at 60mph, I get a horrible vibration. The whole like car shakes, it seems like it's coming from the rear but I can't be sure. Whats weird is, if I take it higher like 75 the vibrations reduce...
I really can't buy an alum driveshaft and have it not be the problem. I never had this problem without the 4.10's but I'm also pretty sure it didn't start right after.
If I take it to a mechanic, would it be easy for them to figure out the source of the vibration? Or is that usually a hard thing to diagnose?
Is there anything cheaper than $259?
Thanks guys
Joe

 

[Blackened302]

found my fms aluminum d/s at a junkyard for $70 out of the same car i got my tremec 3550 from.

if you're strapped for cash, go junkyard hunting. they usually give you like a 30-day warranty on parts, so you should have more than enough time to install and test it out to see if it cures your problem.

 

[5.0 from 95]

Have you had your tires balanced? Might be time to have them checked. Sometimes it can be the simple things that mess with your mind the most. Cheapest part to check first.


Paul

 

[1TallMF]

When my stock driveshaft got out of ballance, it would shake then entire shifter ( the handle would actually become a blurr at anything above 80mph, and only got worse with speed. A driveshaft vibration is also a much much higher frequency (well, in your case, 4.1x) than the frequency of a tire-related vibration, so its hard to mistake the two. If you only feel it in the rear of the car, I'd be checking for possibly loose lug nuts or maybe improper tire balance (thrown weight). Does the rear-end make a sort of howling sound when this happens? If so could be improperly set gears.

 

[go-stang5.0]

1 Tall is onto it....The driveshaft balance issue would cause the trans tunnel to shake along with the shifter and prolly some rattling in the dash too. I threw a weight on my driveshaft at 160mph and I thought the car was gonna fall apart. My neighbor was in the pass. seat and he thought we were gonna die .

I dunno where the weights are on the stock DS but remove it and inspect it for missing ones. Its also very easy to check for missing weights on your wheels.

 

[Synned]

No howling sound from the rear...and its an automatic so the shifter isn't really vibrating. But the whole car shakes, so maybe it is tires?
I had tires put on only about 6months ago from a reputable shop...but who knows.
What cars have alum driveshafts in them already? Is there a different length for AOD-E and t5?

 

[SublimeRT]

How are the u-joints? A driveshaft is serviceable. A brand new aluminum one is not the only cure to d/s problems, though it's a nice upgrade if you can spare the cash. What sucks is those driveshafts used to be about $150-160 bucks. I bought one recently and couldn't believe it had gone up $100 in a couple years. Anywho, you could have new u-joints put in the stock driveshaft and have it rebalanced by a local shop for fairly cheap. Also how is the tranny mount? Just throwing ideas out there.

 

[HISSIN50]

What cars have alum driveshafts in them already? Is there a different length for AOD-E and t5?

If not mentioned or checked (I'm braindead from trying to figure out Adam's CCRM/EEC issue), check U-joints for slop. This is exactly the kind of issue that is created when they get sloppy (resonant frequencies and all that - certain speeds are worse than others and because it's a harmonics issue, it doesnt necessarily depend upon speed).

As for vehicles with an OEM alum DS, the AWD Aerostars alum DS works as I recall. You have to swap a yoke and maybe something else. I have part numbers saved somewhere if anyone actually finds one of these DS's.

Good luck Joe.

 

[Synned]

The u-joints actually sound like it could be it from what you guys are saying...
I'll let my friend's dad whose a mechanic check it out.

 

[5spd GT]

www.buyfordracing.com is selling the aluminum driveshaft for $230 if that is still an option for you...

I got one a couple years ago for $200...