mattchstik

So my front driveshaft had some pretty bad rattling for a while from a bad u-joint. I finally got around to changing it and when I pulled it off, I noticed the centering ball in the double cardan joint was bad so I replaced the u-joint and the centering ball. Put everything back together. The other u-joints didn't have any play on them so I decided to leave them alone at this point. I bolt the shaft back on and it spins fine by hand with the truck in neutral. I take it for a test drive, lock the hubs, and shift into 4hi. As soon as I go a few feet I feel my truck being slowed. I get up to about 25mph and then let off the gas and the truck comes to a halt as if I'm lightly applying the brake. It is intensified when I turn. When i put it in reverse it seems to coast fine and not bind. I don't have this problem when I don't have the hubs locked and it's in 4wd and it doesn't happen when I don't have it in 4wd and the hubs are locked. The double cardan joint seemed to rotate fine before I bolted it on and I didn't have any cv problems before working on the driveshaft. Any ideas??