5.1 is generally good, unless you aim to change frequently. Can be mixed with 4 and 3.
Best to get the original Toyota. It contains the additives required to keep your seals etc in good shape. Good insurance against failing master or early reconditioning.
My Toyota dealer has nothing else than original toyota 5.1. - 3 & 4 is not available.
But I've heard that some toyota dealers use a cheaper fluid when servicing, to save on expences.
Dot 5 (without the .1) on the other hand, is silicone and should be avoided.
Went to Halfords to get a wire brush and thought I would take a look at the brake fluid. They no longer do DOT3 and the chap said DOT4 would be fine but that I will have to do a full bleed to change all the fluid out.
Some how I think he is not quite right.
So it now seems DOT5.1 ids the way to go...it’s getting a little confusing.
Right I plan on using Motul 5.1 which youcan get from Camskill for a good price at the moment. Is there anything wrong with Motul as a brand or is there better out there and does anyone know how much a 100 would use for a complete flush. Someone said 4l some where I think.