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#20228 02/06/2002 9:06 PM | Joined: Jan 2002 Posts: 17 Apprentice | | Apprentice Joined: Jan 2002 Posts: 17 | What is the best transmission fluid to use in the Hydramatic 303M 4 speed automatic transmission used in a 1956 GMC M-220 Duce and 1/2 6X6. The plat on the truck shows to use OE 10 for below 32 Deg. F operation and OE 30 for above 32 Deg. F operaiton. These are old designations for 10 and 30 WT Non- Detergent motor oil. I have also heard that people are using Dextron III Transmission Fluid. Many of the tractors and some of the automatic transmission trucks are using Trans Hydralic fluid. I looking for the best alternative where I wont have to change oil in the transmission if I use the truck in winter. Please reply or give me a contact that could help me with this.
Kenneth L. Hollingsworth
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#20229 02/07/2002 2:55 AM | Joined: Sep 2001 Posts: 85 Wrench Fetcher | | Wrench Fetcher Joined: Sep 2001 Posts: 85 | I really don't know aboout your truck, i never heard of Motor Oil in an Automatic. I have a Hydramatic in my 59 Cad, and it is supposed to have type "a" fluid. I use,and have been using Dexron for 12 years w/o a problem..
ATF is amazing stuff nowadays. It comes as the factory fill in Standard transmissions in lots of cars. I think you could use Dexron. Just my 2 cents. | | |
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