Bad tire, rim, u-joint,......
Check into a new steering dampner, it's a common cause for shake at speed in a Jeep, but it could also be alignment or balance.
Have you checked your tires lately are they old, need rebalanced? It also might be the steering stabalizer, the bushing do wear out after a while.
i ain't no expert but might be the head gasket.
could be a problem with your transmision, having trouble shifting
check your tires they mite be off balance are you have a u joint problem
major vacuum leak?
u probabily need an alignment u probabily need an alignment
I don't know you tell me.
two hands reaching each other to shake hands
Sounds like wheel balance, but check the steering dampner.
Wheel balance, bent rim, bad tire or worn steering components to name a few.
U-Joints are busted.