Transmission Fluid Change
How are transmission fluid issues diagnosed?
Transmission fluid and filter changes normally do not require a diagnosis. They are most often completed as scheduled maintenance, or as part of a repair that requires draining the transmission fluid. If the transmission is being diagnosed for other issues, the fluid and filter may be replaced as a step in the diagnosis, or the transmission may require flushing.
How does transmission fluid work?
Like engines, transmissions use oil (or transmission fluid) as lubricant for the many gears and shifting components that drive the vehicle. The fluid used in the transmission is constantly degrading from age, heat, crushing force and high pressure. When it degrades, it becomes unfit for use and must be changed before permanent damage is done to the moving parts of the transmission.
How is transmission fluid replaced?
For many transmissions, the transmission oil pan must first be removed in order to change the fluid and filter. The transmission pan gasket, which is the most common source of a transmission leak, is replaced as part of the service. The filter typically has only a few screws at most, and the transmission pan can be replaced and filled with transmission fluid.
What to look out for when dealing with transmission fluid issues
We recommend using replacement transmission filters that original equipment manufacturer-quality or better. Inferior filters can let through small particles that can quickly damage internal components. By using a quality filter, the transmission is protected from these particles.
There are many types of transmission fluids, and they aren't typically interchangeable. Check your owner's manual to ensure you have the correct fluid for your transmission. If the wrong transmission fluid is added, the resulting damage could be severe.
Can I replace the transmission fluid myself?
The average do-it-yourselfer can change transmission fluid without too much difficulty. The biggest issues tend to be with pumps for European vehicles and over-tightening the transmission oil pan fasteners. As long as you have the proper tools, and the correct fluid has been selected, the job should be dirty but doable.