97 ram 1500 jumping when slowing down

Hello.  I recently bought a 1997 dodge ram 1500 4x4.  For
some reason once you get the truck above 35 mph or so,  
and let off the gas,  the front of the truck starts bouncing
and popping very violently. (without braking)   In the midst
of the bouncing the wheel studs keep breaking off of my
front passenger side wheel.  It has broken the studs 3
times.  I assumed that it was trying to lock into 4x4 while
driving and when it does the resistance causes the wheel to
snap off.  However,  I removed the front drive shaft and it
still does it.  Am i just going to have to replace the entire
front axel?  All of the front suspension has been replaced
as well as the hubs.  Thank you in advance for any help!