dexron 111 with castrol z - oil compatabilaty - mainsmonkey

I have a hilux surf and auto box runs using dexron 111 oil.Now because its my everyday car for work and towing trailers and a large caravan around europe,.I would like to know weather replacing the dexron 111 gearbox oil with the synthetic castrol z oil is possible.Would i have to have the box completley flushed before changing the oil,or can i just drain the old oil out of the gearbox sump and refill with castrol.As i know some dex 111 oil would still be in the tourque converter,would this matter.I would like to do this because the surf is clocking up around 15ooo miles of towing plus all the weekend run around stuff, and i think the old girl deserves the best oil to keep her going.i,ve had the surf for 4 years and 73,000 miles and never missed a beat.She,s got 169000 miles under her bonnet and still going strong,i just think if there are better oils on the market the surf deserves it.can anybody give me an answer.cheers

dexron 111 with castrol z - oil compatabilaty - RT

Castrol Transmax Z, if that's what you mean, is Dexron III compatible - but Transmax Z isn't generally available in the UK.

I'd have thought that Toyota Hilux Surf was "old school" and any Dexron III would do - the benefit being new ATF, not the particular brand.

dexron 111 with castrol z - oil compatabilaty - mainsmonkey

Yes i do mean castrol transmax z. Thanks for the advice.I just wan,t to look after the surf because some of the people i work with spend fortunes on keeping their modern vehicles going.And i can,t think of anything worse than spending my hard earnd cash on keeping a new vehicle on the road.I was only thinking if there is a better modern oil available i would use it. i guess i will stick with the genuine toyota oil i use.thanks for your time.