66 Ford F100 front end shaking.

I have a 1966 Ford F100 It starts shaking at about 65mph. I replaced the kin pin on one side the side that is shaking. Replaced Shocks on the front. New tires One rim was bent I had it repaired.  Replaced the trans mount. Had the drive shaft u-joints replaced and had drive shaft balanced. Its a lot better but still Shakes. There is a lot of play in the rear end pinion to ring gear.
Can this cause it? Any other ideas?    

a few different things could be happening...

do you have some quality jack stands.. support the rear end on the jack stands..  so its firm..  with care.. run the rear wheels up to speed..   do you feel a vibration..  drive shafts can cause a vibration   with excess clearance between the drive shaft yoke where it slips into the tail housing of the transmission..  at  65 MPH the drive shaft can cause vibrations at this speed..

loose pinion bearings can also.. allow the rear yoke to wobble slightly.. again causing high speed vibration..    

please.> DON'T get wrapped up in the spinning drive shaft..  don't climb under the truck while the wheels are spinning..  this is just a quick test..  to identify if the vibration you are feeling is coming from the drive shaft..





do you have a friend who could drive along side and observe the shaking.. DO NOT HANG OUT THE WINDOW...  

is it going up and down..   showing the shocks are not enough to dampen the suspension..  or the wheels are out of balance.. are the tire weights only in ONE spot on the inside and one on the outside..    its really really important with any kind of light truck tires.. but i don't know if you have passenger car rated P tires or Light truck LT tires..   light truck tires need to be driven until they are worm.. 4 or 5 miles.. and as soon as you stop.. somebody with 2 floor jacks lifts them off the ground so one spot is NOT cooled by the pavement..  this will usually get rid of the flat spots that are really hard to balance out on a spin balancer..


next... with the front wheels straight ahead..    reach through the open drivers window.. while standing beside the truck..  how much does the steering wheel turn before the front tires react.

you could have slack between the end of the steering column shaft right at the coupling joint..

the pinch bolt where the steering box side of the coupling joint could also be loose...

the steering box could be out of adjustment..  or worn..   this is NOT a job for untrained people.. its really easy to screw up..   if you intend on trying.. do post.. .. wheel alignment techs are used to doing this adjustment ..  and get it right...

you could have bad tie rod ends or drag link.. where the pitman arm tries to push the steering linkage but the wear in the tie rod ends is just too much..

having someone rock the steering wheel back and forth to the limit of the freeplay while you lay under the truck observing the tie rod ends .. that they are instantly delivering the motion..

that there is NO slack in the tie rod ends where one will move.. then the part attached to it will move a fraction later...

on ford trucks.. there is also a cross member near the steering box.. i have found the bolt there loose.. so the frame twists with the box as the steering linkage exerts sideways force...

i have also.. usually on mid to late 70's models.. found the rivets that hold the I beam axle pivot brackets loose.. so the brackets are shifting.. ...