biggest engine/transission shakes

[2002V70XC]

I'm facing the biggest problem with my car right now! Its making me feel frustrated!
Its not an urgent problem to fix because it had only happened twice at the same roundabout. I'm not sure if its the transmission or valvebody or engine problem but here is my description of the problem:

Both times it happened at the same roundabout when I did a U turn.
I entered the roundabout slowly just like when you are slowing down for a right turn.
When the car was going slow enough, I released the brake and started making the U turn.
Before I completed the U turn, I gave it a quick gas while the car was at position roughly between 50* or 90* using the road as the base horizontal line. A graphical picture (my car is represent by a forward slash):
---------( / )----<--<---------
Then it happened and it felt like the engine wanted to jump out or more like a massive shake that is much worse than a transmission 2-3 clunk problem. I think I can definitely reproduce the problem but I'm scared that I might destroy something for doing that. It wouldn't happen if I push the gas pedal slowly.

I'm thinking that it might be the Valve body that I bought online because after the valve body replacement, I noticed that sometimes the car doesn't pick up the gear properly. I'm talking about going at 80km/hr and then release the gas so that the car would slow down by itself, then give it a quick gas when it get to around 50-60km/h and the rpm is close to 1000. it would give a rough gear pickup that I would feel at the valve body or transmission. It doesn't do it all the time though.

I don't know what to do now! I still have my spare valve body at home but....I'm not confident rebuilding it myself.
Anyone has any similar experience?
Advices are welcome!

[vtl]

What is your B4 servo cap story? Was it replaced?

[JRL]

Probably IS the VB but depending on your mileage a new or cleaned/rebuilt one may or may not fix it.
There's the law of diminishing returns and the mileage.
It's a 2002, known for bad transmissions

[2002V70XC]

What is your B4 servo cap story? Was it replaced?

yes it was replaced with the one I bought from IPD. That didn't really do anything to help fixing the tranny problems.

[2002V70XC]

Probably IS the VB but depending on your mileage a new or cleaned/rebuilt one may or may not fix it.
There's the law of diminishing returns and the mileage.
It's a 2002, known for bad transmissions

Maybe the VB I bought didn't work properly or something. I didn't get my VB rebuilt but bought 1 rebuilt unit instead.
Driving straight isn't so bad (only noticed rough gear pickups if I played with the gas pedal) but this is so bad that I wanna get rid of the car.

[ericjp]

I'm wondering if it could be a drive shaft/cv issue. What happens if you accelerate hard when you come out from a side street to a main street?

[2002V70XC]

I'm wondering if it could be a drive shaft/cv issue. What happens if you accelerate hard when you come out from a side street to a main street?

I will have to do some test runs to find out. What would happen if it was a bad driveshaft?