Transmission fluid is the connection between the transmission and the engine as it works to lubricate and cool the system. Maintaining and choosing the appropriate transmission is crucial in preserving the life of your car and transmission. Traditionally, car manufacturers have designed transmission fluids for use with specific vehicles. This has changed slightly as more companies have begun to produce alternative fluids that are applicable to many different transmissions.

Manual Transmission Fluids

You can use regular motor oil to lubricate manual transmissions. The viscosity and weight of the oil is typically determined by the type of motor oil you use for the engine. The average vehicle uses 10W-30 or 10W-40. 10W-30 is lighter and tends to work better in cold temperatures, as these are easier on the transmission parts. 10W-40 is heavier and should be used in warmer climates or during the summer season. Hypoid gear oil may also be used for manual transmissions.

Automatic Transmission Fluids

The owner's manual for your vehicle will specify the exact type of transmission fluid you should use for your car. This will avoid complications with your automatic transmission. The type of transmission fluid varies because, while transmissions perform the same basic functions, the diversity in manufacturing and design makes each vehicle unique in terms of maintenance requirements. The main types of automatic transmission fluid are Type F, Dexron III/Mercon and HFM-style fluids. Type F fluid was originally designed for bronze clutches in Ford vehicles. Bronze clutches have not been manufactured since the early 1970s, so Type F fluid is used only in antique or classic cars. Dexron III/Mercon is the most common automatic transmission fluid and is used mostly in Ford, GM and the majority of imported vehicles. If Mercon V is suggested by your owner's manual then use that formula specifically; but all other versions or variations of Dexron III/Mercon should be compatible when these are called for. HFM-style fluids provide friction characteristics that differ from Dexron III/Mercon. HFM is an acronym for highly friction modified fluid. Whenever possible, it is best to use synthetic transmission fluids as opposed to standard fluids. Synthetic transmission fluids tend to be more expensive, but they are worth the investment because they do a superior job of lubrication and cleaning corrosive buildup.

Source:

Fischer Auto

Transmission World