Outer Limits 4x4 Board

Hi all,
after some help to pin point these 2 probs.
1. when criusing along (not accelerating or decelerating) you can feel and hear a fairly big vibration, just wondering if this could be worn uni joints and how to check there condition.
2. there is a leak around the 'handle' you use to lock the hubs it's not big leak and I'm greasing the bearings this weekend, would it just be that the seal behind inner cone is shot?
Thanks,
Luke

For the leaking FW hub, have a look at the 'o'ring between the 'handle' and the body.

Where is the vibration coming from? Steering, front end, rear end...??