Get the fluid and filter changed by someone who knows what they are doing.
Use the toyota ATF.
I don't know if Lucas products (www.lucasoil.com) are available in the UK, but thier Automatic transmission fix may resolve your problem. (what I use on old cars on this side of the pond)
3-4 days after getting the fluid changed follow the instructions and put in the Lucas. It should fix the problem.
check what the germans call the "u-joint" as well. ask your mechanic, he will explain better then I can, its part of the drive shaft. If those pads are worn, it can cause your problem.
