Driveshaft vibe solution

[BullittAndy]

I've been chasing various vibes and have drastically reduced most but still had the classic driveshaft vibe at 75 MPH.

I bought a driveshaft balancer from balancemaster.com and installed it but it didn't work. All it did was change the sound/frequencyof the vibe. In addition, it has metal flanges surrounding it that hit the driveshaft tunnel and brake line-not good.

I then used a giant hose clamp, like has been suggested before and after fiddling with about 8 different positions dramatically reduced the vibe. The car may even be back to normal but I can't tell because this is the only Fox I've had.

Be prepared to commit yourself if you try the hose clamp method because I got lucky and hit the sweet spot after two attempts and then tried fine tuning it by rotating the clamp slightly clockwise and counterclockwise. On my car moving the clamp as little as 1/4 inch lost the balance.

Edit- This is an aluminum driveshaft-brand new.

 

[Dean85GT]

I balanced my stock one and it still vibrated. I just went out and bought an aluminum one.

 

[86bluecobra]

any chance you could have taken that driveshaft to a shop to see if it really was balanced. Perhaps it has a flaw in it.

 

[BullittAndy]

I had the same vibration with the stock shaft as is, stock shaft rebalanced, used aluminum driveshaft and a new aluminum driveshaft.

It appears to a consequence of having 4.10's. I followed a link here that said that 3.73's and above rear gears lower an inherent driveline vibe. (I've got 4.10's)

 

[HISSIN50]

Andy, did you come across a pretty old post by Don? IIRC, he once posted some files of the different positions he tried with the hose clamp, etc. It was pretty good info as I recall, and might be nice just for comparison's sake.

Nice work!

 

[BullittAndy]

I might have read that post, I've been looking at vibration posts for a while. My car was a classic example of the difficulty tracking down vibes because every thing was worn, I've replaced:
-motor mounts
-tranny mount
-exhaust mounts
-engine balancer
-door/hatch/sunroof weatherstripping
-dynomatted interior
-new brakes
-new wheel bearings
-new wheels/tires
-new shocks
-new rear control arms
-jacking rails and matrix system
-new driveshaft (x3)

each repair helped quiet the car down and now its about as good as it can get. Its depressing though because by comparison my 230,000 miles 97 Infiniti Q45 is 10,000 times quieter and perfectly smooth.

I'd love to go back in time and drive a brand new Foxbody to see what they're supposed to feel/ride/drive like.

 

[Darkwriter77]

I've got the same vibe issue at about 80mph ... or probably actually 75mph, since my speedo's a tad off at higher speeds.

Had it with the stock steel driveshaft, so I swapped in an aluminum FRPP shaft. Same thing, same speeds. Replaced the flywheel when I did the clutch, replaced both motor mounts with 'vert rubber mounts, and a poly trans mount. Still no change.

Oddly enough, the only thing that seemed to affect it was switching my exhaust out at one point. When I had the side-exit Dynomax setup, it actually LOWERED the speed at which the vibe began; switching back to Pypes Violators with rear-exit tails RAISED the speed at which it vibrates. So, for a long while I was just convinced that it was an exhaust resonance issue. But the more I think about it, it still doesn't completely make sense.

Oh well ... car's likely to sell this week, so I guess I'll never have a chance to really nail it down. Compared to my Town Car, my notch feels like a 225-horsepower vibrator on four wheels (which really makes me wonder why my ex hated the car so much).