I have a 92 f150 4x4. When i hit about 50mph and higher I can hear what i think is vibration. The shifter for the 4-wheel starts vibrating real hard. Truck drives straight and there is no vibration in the steering wheel.. Anyone have any idea what could be causing this? Or is this normal for an old truck? this is my first truck and i don't know much..

 

Check your u-joints

 

Checked the u-joints and there is no play other than a very small amount in the trans.

 

Have you checked to see if any of the weights on the driveshaft have been knocked off

 

I found 3 weights on there. 2 in the front and 1 in the back.. the u-joints look pretty new. could the drive shaft been put on wrong? or does that matter?

 

When you let off the gas does it die down at all, or is it a constant vibration?

When my ujoint was going out, if I was on the gas it would vibrate, off the gas it died down quite a bit....

 

Yes it dies down but i'm thinking cause the truck is slowing down. It still vibrates pretty hard though after i let off the gas till i hit a lower speed.

 

Verify someone hasn't locked in your hubs while you were parked somewhere as a joke. That will backfeed through the front driveshaft into the transfer case, and cause vibration at a high speed like that.

 

i checked the hubs and they weren't locked..

 

Had the same issue before.......the caps were almost gone.