vibration problem

I know I need to post a picture of the rear setup on my dually but I am at work and no picture.Okay since I have bagged the dually a 1979 long wheel base in the signature, I have a bad vibration from 40 to 50mph.You can still feel past 50 but not so badd.I have new tires balanced, all new drive shaft balanced.I raised the carrier bearing around 2".Have rhe right pitch.My friend Rocky at Fresh Rides looked at it and Mike at Chatoic Customs and both said everything looked good. I did not have that vibe before, unless it was there and the stiff springs were forgiving.I have tried different rims etc.The only thing I have not did was rebuild the rearend.Everything is new but the rearend.The vibe feels like there is no shocks and the rearend shimmys up and down.Can a badd rear end cause a vibe?

Sounds like a bad carrier bearing to me....JM2C

^^^That's kinda what I'm thinking, too.^^^

The whole driveshaft was rebuilt by nw drive train,new carrier bearing etc. I have a dana 70 rearend.I was told the drums ma need to be balanced .The fellow also pointed out how factory drums have grooves cut on the outside edge from balanceing.Any body heard that.

Just give up and scrap the truck.

I've never had to balance drums. Doesn't make sense to me. Seems like if thats the case, you'd have to get them balanced every time you machine them.

But what do I know? I'm just a whiteboy from SoCal.