hydromatic from 1960

I have a 1960 390 and matching transmission. I need to fill the tranny with oil. Should I use synthetic or regular dextron oil? It is not a rebuid trany, just a reinstall after sitting for 5 years while restoring the car.
Thanks in advance, George.

 

I would just use regular Dexron if it were up to me..

 

After replacing front and rear seals, then use Dexron III /Mercon. Would think that would work, that is of course if you want to go out and buy Type A fluid at a place that still carries it.

 

use dexron 6 -updated dexron - good back to 1955

 

I have done many changes of the older trannies to synthetic oil, ( I've been using and selling synthetic oil for over 26 years ), and have never had a problem. The last car I did of my own was a 390/C6 powered 67 Comet conv. The car shifts faster and I also put synthetic 10W-30 in the engine. It runs cooler, starts quicker, and I get better mileage on the synthetic oil.
Bob