Vintage Cars: 1972 350 SL, dextron iii, mileage cars

Question
QUESTION: Hi Ron

I am about to change ATF fluid and filter. (4 years and 11.000 miles since last change) 95.800 miles total. Do you reccomend using Dextron II as originally recommended by Mercedes or is there any reason/advantage by using Dextron III ? are there any exact specifications I should be aware of ?

By the way I am still looking for cheap Euro headlights in Denmark for you. They are not easy to come by.

Thanks again for for your help.

Best regards

Kasper

ANSWER: thanks on the lights, keep looking!!

Dex III  for high mileage  cars is what I use.  
Dex II is no longer used or made , you may find some old stock

---------- FOLLOW-UP ----------

QUESTION: What interval do you reccomend for the ATF fluid change with a very light use approx 2.500 miles per year - the fluid is still bright red ?  I will keep looking for those headlights.  

Thanks a lot for your time.

Best regards


Kasper

Answer
well a good rule of thumb is 12-15,000 miles.  However if the car sits a lot outside and is not routinly driven  and if climate is humid ,wet and with  hot and cold ranges , the fluid has a tendency to become contaminated with  water.  In that case I would not go longer than 3 years , no matter the mileage.  Some will disagree, but this is my rule of thumb