Still Havent Rebalanced/Replaced driveshaft (vibration) anything bad happening?

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Stangbear's right - on my SCCA racer, a failed ujoint caused a driveline vibration so bad that I actually cracked the tailshaft housing of my tranny. Granted - the car was being 'used' very hard, and we were running at high speeds - but vibration breaks things. Get it fixed - dropping a driveshaft is no fun at all. At best you're stranded. At worst, the front end drops at speed and (it's Olympics time) you're pole vaulted into the air.

Vibration there could be a balance issue, it could be a ujoint issue, it could be a rearend issue, it could be a driveline angle issue (if ride height has recently been changed), it could be a speed issue (if rear gear has recently been change) -- there's lots of things that can cause vibration in the shaft that have nothing to do with the dynamic balance of the shaft.
 
I will add that one thing that contibutes greatly to driveline vibration is the amount of rotating mass. If I were you, I would purchase a new aluminum shaft. They are $160 or so through jegs or summit last time I checked. A shaft that weighs less is the way to go, especially if you have lower gears in the rear that cause the shaft to spin faster.

I took my shaft to a driveline shop and they spun it on the lathe. It was twisted. They sold me a steel shaft for $300, I really got shafted if you will. I didnt know I could have an aluminum one for cheap, and they sure werent going to tell me. :D
 
jerry beach said:
I will add that one thing that contibutes greatly to driveline vibration is the amount of rotating mass. If I were you, I would purchase a new aluminum shaft. They are $160 or so through jegs or summit last time I checked. A shaft that weighs less is the way to go, especially if you have lower gears in the rear that cause the shaft to spin faster.

I took my shaft to a driveline shop and they spun it on the lathe. It was twisted. They sold me a steel shaft for $300, I really got shafted if you will. I didnt know I could have an aluminum one for cheap, and they sure werent going to tell me. :D

They actually raised the price for the FRPP aluminum driveshaft. Summit now sells it for $249.95 for the 79-95 5.0s.
 
Aluminum prices globally through the roof right now.

It's not too often that a driveshaft goes out of balance. It pretty much has to throw a weight off - did that happen? Usually when a vibration occurs there it's because of bad ujoints, a rear gear change that has the shaft spinning faster than it was before - and therefore magnifying a slight imbalance that already existed, or something hit it and bent it slightly. It only takes about .015" on runout to make one vibrate like crazy - so it doesn't take much of an impact to screw one up. I'm harping only because I'd hate to have you pull it, have it rebalanced only to find out that that wasn't the problem.
 
jerry beach said:
I will add that one thing that contibutes greatly to driveline vibration is the amount of rotating mass. If I were you, I would purchase a new aluminum shaft. They are $160 or so through jegs or summit last time I checked. A shaft that weighs less is the way to go, especially if you have lower gears in the rear that cause the shaft to spin faster.

I totally agree. However, recently, the price of the FMS shafts went up to over $250. They are still a good buy. I highly recommend one.
 
That reminds me, I need to get the Driveshaft rebalanced. I have the FMS aluminum one, but when I did the tranny swap I had to use a different yoke, which threw the balance off the d/s. Thanks for the reminder since my car is in the air.
 
I bought the FMS Alum DS to cure a vibration after my 3.55's were installed. It cured the vibration, but now there are clearance issues with the muffler, ebrake, etc... so I'm thinking of having my stock one rebalanced and reinstalled.
 
fivepointohgt said:
They actually raised the price for the FRPP aluminum driveshaft. Summit now sells it for $249.95 for the 79-95 5.0s.


Hey what kinda power are you making with that combo? Which mcleod clutch are you using , the dual friction? Where did you get it?

Fyi, you can still get aluminum driveshafts for $199. I just got mine last week from d&d perf for $199 with the needed 31 spline yoke for the tko :cool:
 
i have been having vibration isues at about 85 90 mph aftr i got my 3.73's installed this summer. What kind of cost are u lookin at to get the stocker rebalenced, and where or what kind of place does D/S balancing?
 
At a driveshaft shop. There's one right down the road from me, called Overland Driveshaft. Pretty strait forward, check your yellow pages. Usually about $50. However, changing a DS isn't that big a deal, it has to come out anyway to be rebalanced, may as well spend another $150 and just put in an aluminum one instead.