Automatic Transmission Fluids

• The three big automakers in the United States, Ford, GM and Chrysler, all designed their own specific transmission fluids to apply to their transmissions. Type "F" was the original Ford transmission fluid, but was upgraded to Mercon, and then experienced several different phases and upgrades. GM Motors used Dexron, and again, integrated several different redesigns and phases of the transmission specific fluid. Chrysler did the same thing with their 7176 fluid.
  
  Most all domestic and import vehicles require specific fluids for their automatic transmissions because of a wide variety of reasons directly related to their type of transmission. While transmission fluid is primarily used to lubricate and cool the internal moving parts of the transmission, because the transmissions are so diverse between different makes and models, the type the vehicle calls for should always be adhered to.
  
  You can discover what type of transmission fluid your vehicle takes by reading the owners manual, purchasing a vehicle specific repair manual, calling a local garage or dealership or looking it up online.
  
  

Manual Transmission Fluids

• Manual transmissions often use regular motor oil, but employ a specific weight and viscosity. Hypoid gear oil is commonly used as well, nowadays. Some vehicles with manual transmissions may even use automatic transmission fluid to lubricate and cool the manual transmission system.
  
  

What You Need to Know

• Asking the question of what type of transmission fluid brings to mind the reason why you need to know. If the vehicle is low on transmission fluid, chances are there is a leak in a seal somewhere, and that would require repair.
  
  Do-it-yourself transmission pan drops are an adequate service for maintenance intervals, but you should know that transmission systems use 12-16 quarts of transmission fluid. Transmission pans rarely hold more than 5 quarts of the fluid capacity. While you're thinking you're performing a necessary evil by changing the internal filter, dropping and draining the transmission pan only replaces 1/3 or less of the fluid. The new fluid will be diluted through the other old, dirty fluid stored in the torque converter.
  
  Transmission flushes are a far more superior service to pan drops. It's not to say changing the filter isn't a good idea, but flushes replace all of the fluid, and some claim to restore the filter.
  
  Synthetic transmission fluids are far superior to regular fluids because they lubricate better, clean corrosive buildup better and do not break down chemical composition as quickly as regular fluids. Synthetic fluid is more expensive than regular, but a couple hundred dollars every 30,000 miles is a much better repair than a two to three thousand dollar transmission replacement.