Driveshaft Vibration

So I finally got around to getting my driveshaft fixed. I took my spare driveshaft and filled in the carrier bearings with Polyurethane. It took almost a week for it to cure completely. Last night I swapped out the two and took it out for a test drive. I am getting a lot of vibration at about 60mph. I mean it is vibrating my seat like crazy!!! I can feel it also at other speeds but 60mph seems to be the sweet spot.

No I have run this driveshaft before and didn't have the vibration issue, just bad carrier bearings. when I filled them in with the Poly I made sure they were square and centered. Now I don't have the thumping in the DS anymore but I don't know where the vibration came from. I am thinking that maybe I didn't install the spacers correctly. I installed the taller on the rear carrier and the shorter one on the front. Is that correct???

My spacers are a little worn down also "Rubber is falling apart". so I need to get them replaced.

Are you sure the U joints are good? I know if they are getting stiff they will cause vibration.

More than likely just isolated the fact that the driveshaft itself (i.e., ujoints) is bad. Having the solid carrier is simply transmitting the vibration that has always been there... Can try clocking the shaft against the rear diff and see if that alleviates it.

EricB

Yeah I checked all of the U-joints and they are all good. No stiffness in them at all.

@eric - Clocking the driveshaft?? as in unbolting from the rear dif and rotating the holes 90 degrees???

Yes, clocking. Manual suggests marking prior to disassembly iirc

Sent from garage

Yeah... Marking wasn't an option. No Driveshaft on car when I got it!! The driveshaft that was on there was swapped out with another one. Unless the marks would just transferred over.


So how does clocking the driveshaft help??? I can't seem to visualize it. Taking a rotating assembly and rotating it to alleviate vibration?!?!?

If clocking it doesn't work, maybe send your driveshaft into Mark William's Gonzo? He has a high speed propshaft balancer He rebalanced my ACPT 1 piece CFDS for $125. No more vibrations at all. Well worth it!

There's weights welded to the different sections of our driveshafts. If you swap out sections or get them out of sync the driveshaft whon't balance out. It gets out of phase and vibrates.

Ahh OK that makes sense now.... Thanks I'll clock it and see what that helps.

So I clocked the driveshaft at the dif and that got rid of about 90% of the vibration. I'm thinking the rest is just due to the carrier bearings being solid now.

Thanks for the info everyone!!