Driveline vibration, out of balance driveshaft?

[Jon Hendrix]

So I have a spicer 1 piece ds in my 05 gt. I've had it installed since August, I read that to reduce potential NHV I would need to adjust pinion angle/ ds angle. As I didnt have nhv at the time I put that on backburner as I did other work on my car.
Fast-forward to this last week, and I have just finished fixing a leaking pinion seal. Before I did this job I had an occasional vibration low in the rpm range of any gear. Now, after doing the work, the vibration is worse, but still the same symptoms.

Best way I can describe it is an out of balance driveshaft feeling. Stuttering through acceleration, momentum keeps halting briefly with no unusual variance in engine rpm. There is also a constant rubbing noise, as if my tire was hitting something, and that noise is the exact same noise I get when I experience this halting acceleration, only quieter. Almost as if i have a constant noise that when it reaches the worst point it manifests as harsh stutters.

I have no rear end whines or howls, which is the most common symptom of an improperly torqued pinion flange nut, and the condition gets better rather than worse with speed and rpm.
Im suspicious of the driveshaft being out of balance, but I cant see any cause for how it would be giving me trouble now and not on the initial install.

Any thoughts would be much appreciated, I will provide more updates, clarity, and potential videos as requested.

Thanks!

 

[DieHarder]

Could be out of balance; could be something else since you ran it without doing the adjustments recommended. Suggestion: Take it to into a shop that specializes in drive lines. They should be able to tell what the issue is fairly quickly.

 

[brasil]

...pinion seal. As far as I know, there is no SAFE way to change the pinon seal without renewing the crush sleeve. So perhaps there was just a little play within the pinion bearings. And when the seal was changed, the play wasn´t bought back to the specs...
When I changed the diff bearings, I installed the solid sleeve kit - a little hassle, but well worth the work. So when it comes to the pinion seal job, the retorque is fairly simple.

I have the Spicer /Dana FR DS also in my 2010..and had the same in my 2008 Mustang. And the DS is a real good one ( well made ) in my opinion.

So my bet is on the pinion bearings..

 

[JC SSP]

Brasil, do you think a simple re-torque of the nut will solve the problem?

 

[GriffX]

You can re-torque the pinion nut, stay below 175 Nm. That is the torque spec of a solid spacer, so tight enough for the pinion nut but below the crush torque of the crush sleeve, which is above 200 Nm.

 

[brasil]

@ JC SSP. I agree with GriffX. Try to re-torque . And stay below 175 NM !!

 

[carylarock]

I don’t know how low your car is. But it may be pinion angle. Also if you have had your transmission off it is very easy to install the trans mount back in UPSIDE DOWN. This will change the pinion angle. I have a similar issue I am buying an adjustable upper control arm to help dial in the pinion angle. My vibration is at 80mph plus.