synthetic auto trans oil

I would give your Toyota dealer a call as I think all auto's have synthetic oil as standard and if towing should be changed every 80,000 k's.Do my cruiser that way and in 150,000 k's never had a problem even in 50C+, towing a 19' (GCVM 6.5T).

Darrell

I have been down this path recently after my 100 series TD 5 speed auto transmission failed at 185k and had to be replaced with a new box [along with the torque converter, transfer case and main computer].

The standard oil is Toyota Type IV - a semi-synthetic oil. Toyota have a fully synthetic oil. It appears that the oil type is defined by the actual transmission unit fitted to your vehicle. Early 5 speed boxes have a dip-stick and later ones are sealed. Type IV oil is generally used with the dip-stick boxes and fully synthetic is used in the sealed boxes.

As far as the local Toyota dealer is concerned, towing a 3 tonne van is considered extreme towing and consequently requires that the transmission oil be changed regularly [20k intervals] but only with Type IV transmission fluid. He contacted the Toyota internal technical advice people who strenously advised against use of a fully synthetic where the box has previously used Type IV oil. My new box has done 25K with replacement Type IV at 21K - it appears to be functioning well even on hot days. I am considering a transmission temperature guage to better monitor the situation.

cheers

Searenity

Just had my 2002 LC 100S 4.2 T/D auto trans 'rebuilt' (after 102,000km) and the specialist auto trans shop used Toyota Type IV - at a cost of $146.40! This was for the entire fluid content - don't know how many litres. Having paid $4.2k for the rebuild, I will be careful to avoid 'generic' auto transmission fluids in future and stick with the manufacturer's recommendation (not that the old fluid caused the major problem, but probably didn't help).
Mike