Originally Posted by ggsumo
I thought it was a 5 year / 60K change - mines a manual and it was on my service schedule for last year
We are talking automatic on this thread. Manuals last longer than automatics, and i'm actually surprised it was on a service schedule as the automatic is not because they claim lifelong fluid. Don't even get me started on lifelong fluids.
For a good article on tranny fluids read: How often should the automatic transmission fluid... — Yahoo! Autos
here are some hilites
At elevated operating temperatures, ATF oxidizes, turns brown and takes on a smell like burnt toast. As heat destroys the fluid's lubricating qualities and friction characteristics, varnish begins to form on internal parts (such as the valve body) which interferes with the operation.
As a rule of thumb, every 20 degree increase in operating temperature above 175 degrees F. cuts the life of the fluid in half!
At 220 degrees, which is commonly encountered in many transmissions, the fluid is only good for about 25,000 miles.
According to the Automatic Transmission Rebuilders Association, 90% of ALL transmission failures are caused by overheating. And most of these can be blamed on worn out fluid that should have been replaced.
Example: ATF that enters the radiator cooler at 300 degrees F. leaves at 240 to 270 degrees F., which is only a 10 to 20% drop in temperature, and is nowhere good enough for extended fluid life.
An auxiliary transmission fluid cooler is easy to install and can substantially lower fluid operating temperatures. The plate/fin type cooler is somewhat more efficient than the tube and fin design, but either can lower fluid temperatures anywhere from 80 to 140 degrees when installed in series with the stock unit. Typical cooling efficiencies run in the 35 to 50% range.