moosestang

The one caused by my clutch/flywheel would vibrate my rear view mirror it was so bad, but with the stock shaft, you wouldn't even notice it unless you knew it were there. Speed didn't matter in this case, only the 3200rpms mattered.

Most people with 1 piece shafts complain about vibrations over 100mph. If you never drive that fast, then you may never experience any vibrations. I had a slight vibration over 70mph when my gears were installed. The shop didn't put the shaft back on correctly and turning it fixed the problem.

moosestang

Are you using an adapter plate? The spyder shaft uses a new pinion flange, i'm assuming you aren't using a new flange. Your problem maybe in the adapter.

Riptide

Not that it's a huge issue but at speeds over 100 then vibrations are almost a certainty?

rojizostang

i'm using the pinion flange. the question about how bad it is, really, my vibration is pretty small. the shifter doesn't shake, or the mirrors or anything else. it's as much a slightly audible humming sound with a very slight vibration that's really pretty difficult to feel except for maybe in the floorboard or the seats.

RICVA05

This might seem like a dumb thing to ask but how much thread lock are you using on the bolts when you re-install them. To much can act like a counter weight on the shaft.

rojizostang

i've had shafts on and off so many times that there's actually a little build up of thread lock on some of the bolts.

i actually can feel a little vibe even with the stock ds, i was checking it out closely on the way to work this a.m. i'm convinced the alum ds isn't the source of the vibe, it only makes it show up a little more. i think i'm going to try adjusting the angle on the stock ds and see if that makes any difference (and clean the extra thread lock off) before i go to all the trouble of installing the alum ds again.

MHGT

I agree that the driveshaft is not totally responsible...I have checked the run out on the companion flange and it was almost 4thou out at the inside shoulder that indexes the mating flange of the shaft. I remember reading someplace that from the factory there were some shafts with small shims between the two flanges that would true the runout.....being said that I with a file trued the companion flange shoulder of the 4 thou and installed the driveshaft and it did help....I have installed the shaft both directions and have the slip joint in front now as it has smaller rotating size and should be less mass...it does help but I liked the joint in the back as it seemed to accelerate quicker...but vibration is the problem. I am now going to try changing to a urethane trans mount bushing as when your under there as I am sure you have felt the mount is VERY sloppy and mushy...maybe that allows it to vibrate more out of control ...who knows ...

rojizostang

okay i got off the phone with a guy who is/was a ford dealer drivetrain vibration specialist. he gave me a couple of ideas to try to isolate where the vibe is coming from. he said to run at the speed at which the vibe is the most pronounced in 5th gear...and if it's not too fast....down shift to fourth and gently roll into the throttle. this would help to determine first of all if its a vibration that's from the tailshaft forward (engine & tranny) or from the tailshaft backwards. if the vibe stays the same, then it's definitely a driveshaft/rearend issue. if the vibe changes or goes away at the different rpm running at the same speed, then it's a transmission, clutch, flywheel, engine issue.

also, i never would have believed this, after telling him my angles, he said that i probably need to increase by a slight amount the pinion angle. according to him ford has very specific tolerances that if an angle isn't almost exactly right, vibrations will result. i'm at a total difference front and rear of 3 degrees, and he said i need to at least go to 4.

this is totally opposite what the ds manufacturers have been saying.(at least the ones i've talked to) they say the closer to zero the better...apparently with the 8.8 rear end and all the associated components, it's not necessarily the case.

i have a set of adj lca's on the way, and then i'm going to reinstall everything and go from there. who knows. at the very least i think i've found somebody who can help me work thru this issue.

MHGT

I will guinea pig with you...I was tonight anyways going to turn my driveshaft around as like I said I think it is smoother with the slip in the back....I will adjust my pinion angle to 4 degrees and let you know tomorrow...I have it now at -1, it is really easy to do with the shaft out and only takes 15 mins or so anyways...i will let you know if it makes a difference.
I still think the runout is the key and by running the car while off the ground and watching the driveshaft I have been able to tell when its good or not....you can really see the runout when its there

rojizostang

the shaft i have sitting on the floor i did look at the way you described....it's the best one of the bunch that i've installed, but the vibe is still there, though it's to a lesser degree.