4 x 4 help needed- '86 720

[mpqualdie]

Hello all, I have an 86 720 4X4 I've been restoring and have it just about all done except the paint. I've never dealt with 4 x 4's before, so I'm a little stumped once again. It runs and drives great, but when I decelarate I'm getting a heavy rumble or vibration from the drive train. It will also show up when I hit about 50MPH. I checked the drive shafts and put new universals on the rear one. The front wheel drive drive shaft has a little play in the expansion splines, but not but a nudge. Any Ideas what could be doing this? I know the transmission is fine because it came out of my '85, which ran and drove when I pulled the motor and trans. I checked the xfer case before reinstalling it and it seemed to be in pretty good shape. It didn't seem to have any slop or play. I am going to replace the front wheel bearings next. If it winds up being the drive shafts (expansion splines worn), does anyone know where I can get new ones for that truck. Anything I get from a junk yard would be in the same condition I would assume.
Thanks in advance for all of your help!!!

[Gert]

in South Africa parts are extremely scares so I discovered after much blood, sweat and tears by comparing the fishes and the part nrs that the 720 4x4 and the Hardbody 4x4 86-94 models have mostly the same suspension and axle parts. Also the Pathfinder. Seems like these parts are much easier to find on these models rather than under the 720 as criteria. Be careful on the knuckle joint if you have a 83 model. Also make sure about the hub assay if you have a 83-86 model....Check out http://www.nissanpartszone.com