Fireballsocal wrote:
Toyota calls it lifetime fluid for a reason. You will get the best value from the drivetrain by following the owners manual instructions. You paid a premium buying that truck over a domestic because of the perceived reliability behind the Toyota brand. Let them make the call on when to service the components. And to those doing auto trans fluid changes every 5, 10, or 15K? Really?
OK.. I will bite..
Have you ever thought that the manufacturer would like to ENSURE they will get future sales?
Transmission oil DOES break down, but at a much slower rate than say engine oil..
Transmission oil is basically HYDRAULIC oil, only with a few "additive packages" blended in..
I can tell you this, with owning a tractor with a front loader and backhoe, hydraulic fluid CAN get worn out by contamination from the AIR.. More specifically MOISTURE in the air. Hydraulic fluids are "hygroscopic" , in other words it ATTRACTS MOISTURE..
Learned that the hard way one extremely brutal cold winter when my hydraulics FROZE.. Yeah, the water suspended in the fluid FROZE and plugged the filter..
So, in some respect, "refreshing" your transmission fluid IS A GOOD THING TO DO if you wish to have a transmission with a long, long life.
I will however disagree with folks that feel the need to change out the entire volume of fluid by using a pump exchange or needlessly changing fluid at 30K or less intervals.. I would however recommend reading your owners manual and use their figures for the mileage especially while under warranty.
Forced pumping risks damaging pump seals and many newer transmissions require a HEATED exchange (IE transmission has a thermostat that needs warm fluid in order to open the external cooler circuit).
Personally, I simply dump the fluid that is in the transmission pan (newer vehicles often have pan plug other wise you will need to remove the pan). Then refill the pan.
I have waited as long as 80K miles for the first time since most of my driving is highway miles which helps drive out any moisture that the fluid may have attracted.
Doing this several times over the life of your ownership of said vehicle will refresh the oil.
So far, this has worked well with my 2003 F250, has 200K miles on the transmission and still going!