driveshaft vibration

[Rockybar]

Been hunting a noise, bought 2 u-joints, replaced them both.

Now my noise is a serious vibration at low speed, seems to go away up high speeds.

What could I have messed up?

thanks

[fordman]

Single or dual driveshafts? Dual driveshafts need to be phased. (Ujoints lined up). If single unbolt shaft and turn it half aroynd and put back in.

[hillcountryflt]

Please explain "phased" in reference to replacing u-joints on a long-bed pickup. I have one with the split drive shaft and would be interested in this as I have yet to replace my u-joints on my 69 F100.

[fordman]

u joint caps should line up on both shafts. Be inline with each other.

[fordchris47]

carrier bearing could be broke that's what happened to me, the rubber around the bearing cracked had vibrations at low speed

[mustang68 ranger71]

Thank you fordman, I just acquired a 71 camper special 390 that i a bit of a hot rod. The u joints are going to get replaced soon along with the carrier bearing. That is good to know about the phasing. i would have been chasing that for ever.