Hi All


I am from South Africa, driving a 2013 Lexus GS 250 ex 6 Speed Auto


I have a strange problem. I like to drive the car in manual mode, although this problem does happen in Auto mode as well.


If I am cruising along at 100km/h in 5th Gear and then drop it to 4th Gear the car makes a thud type of noise. Same happens when I go from 4th Gear to 5th Gear.


I had it at the dealer today and then updated the gearbox software and changed the Gearbox Oil. Although the gearbox is a lot smoother now it still hasn't resolved the primary issue


Any idea's as to why this would happen?


Thanks in advanced
Ryan