Unbalanced drive shaft symptoms?

[bloopbloob]

If a driveshaft was not balanced right, what would it feel/sound like? i have a weird harmonic pulse which i think may be from the DS. but it only happens in 5th, and doesn't really change much as rpms change. its worst at about 2800 rpms, and the shifter vibrates pretty bad at that rpm also. ideas?
i never noticed it before the gear swap and trac-lok rebuild....

 

[PUNISHER RACING]

UPPER CONTROL ARMs (sorry about the caps)

 

[bloopbloob]

UPPER CONTROL ARMs (sorry about the caps)

could you explain this a little more please? is the whole rear end moving around then? and why is it ONLY in 5th gear that this happens, and only since the gears?

 

[PUNISHER RACING]

I had a similar problem with a bad vibration that came up through the driveline so bad you couldn't stand to hold the shifter. After changing u joints and driveshaft I come to find all along it was my upper control arm bushings. They were so bad the whole rear leaned forward causing the pinion angle to change for the worst and causing an annoying vibration at highway cruising speeds.

 

[Nova]

did you reinstall the driveshaft on the proper index?

http://www.tccoa.com/articles/tranny/transmission/page17.shtml

 

[MattSVTContour]

did you reinstall the driveshaft on the proper index?

http://www.tccoa.com/articles/tranny/transmission/page17.shtml

Great link!

I have 3.73s and I had major vibes above 70mph until I installed an aluminum d/s. Now the vibes are greatly reduced, but gear noise increased. This article seems to explain all of this.

I guess I just need to invest in some Dynamat at this point to line the floor with.

 

[clayschmuck]

Great link!

I have 3.73s and I had major vibes above 70mph until I installed an aluminum d/s. Now the vibes are greatly reduced, but gear noise increased. This article seems to explain all of this.

I guess I just need to invest in some Dynamat at this point to line the floor with.

Sort of off topic but try fatmat (I think it's fatmat.com). I just installed that in my car and it was a lot cheaper than dynamat!!!

 

[MattSVTContour]

Sort of off topic but try fatmat (I think it's fatmat.com). I just installed that in my car and it was a lot cheaper than dynamat!!!

You are right, either that stuff or RAAMmat.

 

[strtrcr50]

I had a similar problem with a bad vibration that came up through the driveline so bad you couldn't stand to hold the shifter. After changing u joints and driveshaft I come to find all along it was my upper control arm bushings. They were so bad the whole rear leaned forward causing the pinion angle to change for the worst and causing an annoying vibration at highway cruising speeds.

I wonder if that could be my problem. I have a small vibration in 5th and have original control arms/bushings..