Transmission :
If you try to drain and fill the transmission yourself, or even if you take it
to the dealer for their 'drain & fill service' you will only be able to
get out a few quarts of fluid. Most of the old fluid remains in the
torque convertor, valve body and transmission cooler.
I chose to have a "Total ATF Fluid Exchange" using a T-TECH machine.
Many Toyota dealers use this machine, but none had it near me.
I had the service performed at JiffyLube.
ExpressWay also uses the machine.
A T-TECH service flushes the entire transmission system, including the torque converter,
cooler and lines, replacing the old automatic transmission fluid (ATF) with new fluid.
The T-TECH machine was filled with 16 quarts of my own new amsoil fluid then hooked up to the stock tranny cooler lines.
With the vehicle idling, the old ATF is diverted to the T-TECH through the
natural pressure of the vehicles transmission pump causing an equal amount of
new ATF to flow into the transmission.
They say the T-TECH method achieves virtually 100% ATF replacement.
The main drawback is that since the transmission pan is not dropped,
the 4Runner's wire mesh filter cannot be cleaned and the magnets in the
pan cannot be inspected and cleaned. A good thing is not having
to worry about improper sealing of the pan, since it is not removed.
My vehicle had this procedure performed before the manufacturer's recommended
interval, so I am not too worried about cleaning the filter.
Transfer Case and Differentials :
Toyota specifies that the following various drain and fill plug gaskets
are a non-reuseable part. The gaskets are made of metal and deform
when torqued down to form a proper seal. So I replaced them all
during the fluid change.
Always open up the fill plugs first when changing the differentials and transfer case.
You do not want to find out you cannot open them after you drained all the fluid out.
Once you get the fluid drained, be sure to clean off the magnet on the drain plugs that collects metal filings.
A siphon pump, such as the one shown to the right, makes quick work of refilling the cases.
It can be purchased from Griot's Garage, if you cannot find it locally.