We got one of those rare Texas snow storms in February. I locked in my hubs and started down the road. Got a loud clunking sound from the front left. I could feel the vibration in the floorboard.

It does it only when the hubs are locked, whether in 2wd or 4wd. I've been told that the hub is probably not locking in correctly.

If this is the case does this mean the hubs should be replaced? If so, is this a job a relative novice could do?

BTW this is on a 1988 F-150 with a 351 and manual hubs and automatic transmission.

 

Yes if a hub is bad it needs to be replaced. A very bad hub can develop the symptoms you describe, but most usually make a clicking sound when they go out. I would replace them with a set of Warns. If you watch ebay you can get them for pretty cheap though you wouldn't get any kind of warranty on them since most ones sold on there are not through dealers. Its not very difficult to change the hubs out.

 

It could also be a bad U-joint. These will make a clicking sound too. As yours is making the sound when locked in whether in 2wd or 4wd, I would look there first.

 

My brother in law just put in new U joints before I bought it.