Freelander 2 autogearbox sound when accelerating

hello I’m new in this forum so I just bought Freelander 2 XS 2.2 td4, and I have a question is there anybody had same isue like me: when the car is cold its accelerating normaly like with the cold engine sound, but after few km when the engine had some temperature when accelerating I’m listening form the engine or transmision area rattaling sound, and how deep you push the peddle down the sound is going more like revs, and also when going downhill and you not push the gas pedle Im listening the same sound and if you turn the car into N ( neutral ) the sound is stop.. when the car is in P you cannot listen that sound, only under push. Also I saw that if its rainy day and the water splash under the car the sound is getting lower... any idea what can be? And for the record the gearbox is ok when shifting, only when you accelerating from 0 I can feel some little vibration.. thanks for reading such a long

With the Vibrating and the noise i'd say Torque Converter most likely..

Check the fluid level and condition in the 'box..

I just change the oil and the filter of the gearbox and the whole engine. And also in the service found that the “axial mounting” of the engine is brakedown.. so I thought that can cause the problem...