Changed mine by draining out about 2 litres, all you will get from drain plug, and refilling. The ran it for a week and repeated until I had put 10 litres in. Looks nice and clean now and response has improved no end. The old oil was very black. Important to get Toyota fluid and will cost around £100 for 10 litres. Negotiate, I did and got it for trade price, which was about 25% off if I remember right.
Did the power steering fluid as well by using a turkey baster to remove as much as possible from reservoir and refilling several times, running for a couple of days between each change, till it looked clean. Took about a litre.
These are the best methods if you don't fancy pulling off pipes.