Picked up a 1977 F150 4x4 w/ 5" lift and running 37's (new). Vehicle is full time 4 wheel. Have a vibration or more like a hobble in the front around 45mph, the rest of the time nice and smooth and holds the road well. Have not had a chance to get dirty with it but hoping for a few ideas as to what to look for. My thoughts are possible issue with front axle drive shaft or transfer case. I am going to try and get at it this weekend so any help would be appreciated.

 

Idk how these d shafts are set up cause I just got my first dent but firstly check tightness on your u joint straps/saddles and check for wear. Just the obvious stuff. Also check for driveline phasing. If your d shaft is out of phase it will vibrate like crazy. Just in case you dont know (no hate intended of course) phasing a shaft is aligning your end yokes on the same plane as your slip yoke. I work on semi trucks for a living and in my experience even a tooth off on the splines on the slip yoke will cause a steady vibration on the road. Hope this helps.