Time: 30min - 1 hr

Difficulty: moderate

Cost: $60-150

FUNCTION

An automatic transmission is a complex hydraulic pump with gears, clutches, bearings, valves, and actuators. The fluid in an automatic transmisison is used to apply pressure, transfer torque, clean, cool, lubricate, and activate components. To proform its function, it needs to be in peak condition. 

WHY SERVICE

Replacing the filter and fluid often can prevent one of the costliest repairs you can experience on a vehilce, the transmission. Heat, shearing forces, contaminates, and time cause autmotatic transmission fluid to lose its protective properties. As the fluid additives and properties break down, temperatures increase, clutches wear, flow restricts, and components fail.

INTERVAL

Transmission fluid and filter should be replaced on-condition, but it's a durable fluid within a sealed system (excepting vent-to-atmosphere), and therefore is impressively durable. Still, industry standard is anywhere from 30-60,000 miles, depending on driving conditions. Heavy start/stop traffic, hills, towing, extreme termperatures, etc. warrant the earlier side of the range, while long-distance flat driving would warrant the latter. 

What does on-condition mean? New fluid is pink/red and opaque. Spent fluid is brown to black and has a horrible burnt smell. You obvisouly want to replace it before it gets to that point. 

METHOD

Drop the pan, replace the filter, install the pan, and add the appropriate fluid amount. Ideally, you would then procede into a complete transmission fluid exchange. If not, start the vehilce and set the fluid level accordingly. 

RAV4 Filter - https://youtu.be/IjBkvcLTIBo

RAV4 Flush - https://youtu.be/ntFVCVW-lG8

The video below shows how the filter was reeplaced on a 2007-2013 generation Toyota RAV4.