I to have the infamous 1st to 2nd "clunk" and have been arguing the toss with my Dealer for 6 months now trying to get it sorted.
After 3.5 mths my Dealer swapped my clunky gearbox for one from their own Demonstrator car. Unfortunately, that box was worse. Its now been another 2.5 months complaining, culminating in a visit from the Service Manager from my Dealership and Neil Jones, Customer Care Manager for Lexus UK.
Both drove my car whilst I sat in the back and I pointed out each time the box clunked changing gear. I was assured that it was a normal "characteristic" of the box and that they all did that.
I must say that I felt like I was being completly fobbed off - a £20k car, top of all the car polls, all with clunky gearboxes .... I dont think so !!
Both suggested changing the gearbox oil for a heavier oil which would make it quieter but more difficult to change gear.
I opted not to bother with the oil change.
I have spoken to other IS200 owners who have no problem whatsoever with their gearbox ........ yet.
Please let me know if you go ahead with the gearbox oil change and if it makes any difference.
Good luck.
Pete