wierd sound in 4h and 4L...help?

[66broncotx]

I need help with my bronco. i have a 66 with a 170 and a dana 30 front. I took my truck out tonight and attempted to put it in 4h and 4l. I am having trouble with the left side hub, it won't go to the stop and lock in all the time. Even when it does, it still makes this knocking sound every rotation of the tires. This noise sounds like a rotational noise, the faster I go the faster the knocking. This sound only comes from the left side. This only happens in 4h and 4l. Otherwise, in 2h this truck runs great...no bad noises. Has anyone had this happen? My first thought is to replace the hubs(currently...Dualamatic(on when I bought the truck)). Is this type of sound normal if a hub does not engage? Or do I have a worse problem than needing new hubs.

Thank you for your help,

Brandon

 

[edjolly]

It could be the hub, and whatever it is, your going to get into the hub anyway. One quick check: The U-joint on that side. Look at it, grab it and check for slop. It could very well be that.

Ed