Vibrates when going 40-60mph steering not shaking but feel vibration went under truck and could move front half of drive shaft but not the rear half

put tires from rear up front and front to rear and see if tires cause a shake also make sure no debris on hub so rim sits flush if no change and still vibration check drive shaft and u joints

Barbara,
Vibration is caused by something out of balance - or worn.

If your steering wheel shakes and vibrates there's a tyre balance/steering problem.

You say that it is under the seats - this suggests a worn propshaft (driveshaft) which is causing the vibration, or a worn gearbox or engine mounting.

There's nobody on Fixya who can give you a 100% diagnosis without actually witnessing the symptoms themself.

If the vibration is as bad as you say it is - either give a mobile mechanic a call or call in at a workshop and ask them to give you an opinion. If you continue to drive a car that has a shaking/vibration problem you're likely to cause further -more expensive- problems.

Having an alignment done usually only corrects the car pulling to one side. Check the rear tires for balance and wear. You may also want to have them rotated to the front to see if the vibration also moves to the front.

A VIBRATION in the drivetrain is going to be noticeable both during acceleration and deceleration . Sounds like engine skip under a load.

Check the front tyres for hi / low spots, flat spots, bulges. Try rotateing your wheels front to rear & see if the steering vibration disapears & noise move to rear.

GET IT TO A MECHANIC!! Something is loose or about to collapse! Remember that vibration and noise can travel away from the source so get the mechanic to start in that corner.
You need to get the following checked!
-Prop shaft mountings at transfer box.
-Prop shaft mountings at differential.
-Prop shaft bearings.
-Differential condition and oil level.
-Drive shafts at differential end.
-Drive shafts at the wheel end.
-All flexing joints in the system including UV joints and CV joints.

check the front tie rods jack car up and see if front tire moves from side to side or feels loose

Without driving the vehicle, it is hard to say for sure. However, there is a Technical Service Bulletin (TSB) that is published by Honda that involves your transmission limiter tabs (part of the rear transmission mount) causing a vibration while accelerating.
The TSB number is 04-070. I can send you a complete copy of the TSB if you want to post an email address. Or you can also probably get your local dealer to print you out a copy if you don't want your email address posted online. (recommended)

The clunk sounds like it has a bad u-joint in the rear drive shaft. The rattle in the front may be a broken swaybar link.

it sounds like a wheel bearing noise to me. is it constant? Does you steering wheel vibrates shake?