Many transmissions have a harder life than the manufacturer had originally intended. Whether it has found life in a street machine, or it is in a tow truck, a transmission cooler can really help keep a transmission running better for longer. Transmissions wear out incredibly quickly when the fluid gets over the ideal operating temperature. You can find one for around $30 on Amazon or Jegs. They hook directly to the transmission coolant lines and add an extra mini radiator for the fluid to go through. Typically, they are installed in front of the radiator to utilize the freshest air possible. They usually last for the entire life of your transmission.
