Shudder under acceleration

TIA
I’m looking for help to diagnose my problem in my 07 sv6 I put a second hand 5 speed auto in after my torque converter broke down and ruined the box with the metal going through it. 5 month later I have had a gradual shudder start.
When I start the car from sitting over night the whole car has a vibration, reversing off the drive feels rough as then when accelerating fairly hard the car shudder then when let’s say over taking at high speed the shudders turns into a shake of the whole car.
I have changed wheels, tyres, rotors been under the car with my mechanic all bushes and rubbers are average but not broken down all looks fine.
I’m thinking the torque converter as when the car was on the ramp and running in park there was a mild knocking / ticking noise that went when put into drive also no play in the prop shaft and changes gears smooth up and down the range.
Any ideas where to look will be much appreciate as it doing my head in
Thanks

 

Only the gear box end was removed so not sure how it could be installed wrong, but def feels like it’s getting worse but does seem to ease as the car warms up unless I’m giving it a boot full

 

Not sure then I will ask my mechanic I was in the workshop but don’t remember it coming of the car

 

I had a check of the converter bolts to the fly wheel today all good but because I removed the starter motor I disconnected the battery and when I restarted it the problem was hardly there if at all so I’m now thinking it’s a soloinoid problem ??? I didn’t check for faults before I disconnected the battery which would of caused a reset and nothing showed after. So really still stumped

 

Does it go away as u get faster or get worse? it could be heaps of different reasons I’ve gone through a proscess of elimination mate been on the ramps half a dozen times and I’m still going.

 

VT
Yes mate it does although not as bad or if at all once I disconnected the battery yesterday when I was under it

 

I would start with getting the rear wheels balanced then ask the guys to check ur prop shaft rubber donuts, if it’s a good work shop they should have a look for u. If not get a pedders safety check and they will go through all ur bushes.

 

UPDATE

I have changed out centre bearing and both donuts on the drive shaft which seems to have got rid of most of the shake shudder under acceleration.
But still have a vibration while in park revving the engine so changed the engine mounts and it’s still there ☹️☹️☹️
Now I’m thinking it can only be the converter unless anyone has any ideas ????

Any input would be apprieciated