- When it gets cold, parts contract (they get smaller). Tight tolerances become loose and parts tend to wear more quickly. Seals shrink and get hard, and are more likely to leak.
- The transmission fluid gets thicker. Ideally the transmission temperature needs to be at least 195˚ Fahrenheit to function properly. When the transmission gets below zero degrees Fahrenheit it starts to get too thick and loses some of its velocity.
- Shift points become delayed. (Delayed shifts are a precursor to harder shifts.)
- The transmission shifts harder.
- The computer in many vehicles will delay or prohibit the use of overdrive until the transmission reaches normal operating temperatures.
- The transmission fluid loses some of its ability to lubricate internal parts correctly, resulting in premature wear
- Water in the transmission can be a big problem, whether it’s cold or hot. Water freezes at 0˚ Celsius / 32˚ Fahrenheit. This can cause damage to the case and valve body of the transmission, including creating cracks that will leave the transmission in a non-rebuildable state. Be careful going through deep puddles and high snow banks. If you find yourself in either, turn the car off and get it towed to a shop where the transmission can be drained.
- Allow the motor to warm up before putting the vehicle into gear. Modern transmissions rely on information from sensors on the engine. This is a fact that most people don’t know. If the engine is cold the computer will think the transmission is cold, too. The computer will modify the performance of the transmission until it senses that it is up to operating temperature.
- Store your vehicle in a climate controlled garage. The garage does not need to be toasty hot, just warm enough to keep the fluid from thickening and parts from shrinking too much. 50 degrees is a reasonable temperature that will not break the bank.
- Use synthetic transmission fluid. Synthetic fluids behave much better and retain their given specs under cold weather conditions. Be sure to find the synthetic fluid designed for your vehicle. Not all transmissions will work properly with a synthetic fluid.
- Drive easy the first few miles. This will give the fluid and internal parts time to come up to normal operating temperatures.
Originally from ETE Remanufactured Transmissions