I have a 1980 F150 which has developed a major 4x problem. If I lock in the hubs and put the xfer case in 4hi (or 4lo) Everything is fine (front wheels move) untill i get over 15-20mph. Then the truck lurches, jumps, pulls to one side and makes some nasty dragging noise. It does this regardless of the surface. Dry/wet pavement(on dry I can hear a front tire chirp every time it lurches), fully snowpacked gravel roads, even in 6 in of snow. If I have the hubs in but the transfer case in 2hi, everything is normal. It started doing this when it got cold, but this could be a coincidence (hasn't warmed up in the last 3weeks to check). HELP!

 

On the wet or dry pavement, I would say that this is probably somewhat normal for a 4x4. Mine is brand new, and if I drive with it in 4x on the pavement, it drives somewhat ok as long as I don't turn. If I turn the corner, the front and rear bind up, and it takes a lot of juice to get it to go. It lurches, just like you described... From what I am told (and others may correct me if I am wrong), the front axle ratio is a bit lower than the rear, so instead of the rear wheels pushing the front ones around, the front wheels drag the hind ones around, to improve control. All I can say about your situation is that it could be anything from the transfer case (ouch!) to the hubs not engaging properly.. Sorry I couldnt be more help on this, but I just wanted to share my experiences with my new 4x.

 

I have a 92' F-250 4x4 with manual hubs and yes it will lurch while I'm turning but not while I'm going straight. I've gone up to 40 mph while in 4h and never experienced a lurching. You might want to watch someone drive your truck by you doing 20 and see what it looks like from outside the truck. Does it always pull to the same side? Where does the dragging noise sound like it's coming from?

Daywalker
92' F-250 351 4x4 xlt 4.10 5spd sprcab lngbed

 

The Ford TTB system uses 3 U-joints across the front, i.e., two steering U-joints at the knuckles, and one at the pivot point for the TTB.
This leaves one u-joint on the driver's side, and two U-joints on the passenger side. I set that central U-joint a bit tight at last rebuild time, and the truck pulled off toward the ditch until the central U-joint loosened up.
I wonder if your center joint might be causing you some problems?
Eddie

 

OK, this is starting to make sense, On the drivers side I have a toasted ball joint, If i jack up the truck I can move the wheel back and forth about 6 inches on the bottom. I bet you are right with the ujoints, I bet they are binding when the ball joint moves too far, Now I just have to change it (ughh)