PR FIEBRU

There has been a recent trend toward use of fluid evacuation systems in the
automatic transmission service industry in lieu of traditional transmission service
methods. These systems are used to pump the old fluid out of the transmission and
to refill with fresh fluid. This avoids dropping the pan and draining the unit which can
be time consuming and messy. The use of this method to replace the transmission
fluid is a clean, efficient, and safe way to remove hot oil from a transmission. The
problem, however, is that often times it is mistakenly thought that this represents
complete transmission service and that removal, and cleaning of the pan and
inspection and servicing of the filter are unnecessary.

Some people believe that all transmission filters are backflushed clean every time
the vehicle is turned off. This is a major misconception. Three-quarters of all
transmission filters today are not a simple screen, they are made of felt. A felt filter
CANNOT be backflushed. Felt holds dirt particles within tiny pores in the felt. It will
not wash out or flush out. If a felt filter becomes clogged it must be replaced.
Clogged filters restrict fluid flow, which lowers pressure to clutches and bands. This
can cause slippage and eventual burnout of the transmission.

Service manuals and textbooks on transmission service recommend that a
transmission filter be inspected and replaced, if necessary, as often as every 15,000
miles (24,140km), for severe service such as city driving, desert (hot dusty) driving,
extreme cold, frequent short trips, trailer towing, and delivery service. In normal
operating conditions the manuals recommend to inspect and replace the filter at
least every 30,000 miles (48,280km). Even the newer vehicles with 100,000 mile
(160,934km) drive train service warranties, the manufacturer recommends filter
replacement if the vehicle sees severe service conditions.

There have been an increasing number of instances surfacing recently regarding
transmission failures shortly after an evacuation service, without filter removal. At the
time of a fluid evacuation service, there is no way to know the condition of the filter
and how clogged it may be. The filters job is to collect and hold contaminants, (dirt,
metal filings, friction particles, etc.), and prevent these particles from causing
malfunction in such components as electronic force motors and solenoids. Today's
transmissions are far more susceptible to malfunctions caused by fine dirt
contamination. Without servicing the filter, there is no way to know if the filter is clean
of debris or nearing capacity. If the filter is nearing capacity, transmission failure may
not be far off. This is also a sign that there may be other internal problems in the
transmission. Recognizing these warning signs could eliminate major service later.
transmission. Recognizing these warning signs could eliminate major service later.
Most of the transmission failures after an evacuation service have occurred primarily
on relatively high mileage transmissions that have not been serviced in some time.
One reason for this is that the sludge and dirt buildup within the transmission will not
completely be removed during the service. When the new fluid (which has detergent
properties) is placed in the transmission, over days and weeks, the internal
components begin to wash the insides of the transmission.

This sludge does finally work loose and settles in the transmission filter, clogging it
up even further than it may have been before service. In these extreme cases, where
service has not been performed in some time, changing the filter may not completely
fix the problem. Some mechanics recommend a second service a few weeks after
the first, replacing the filter again, which may be partially clogged due to the cleaning
process in the transmission.

Even if the fluid evacuation method is desired to remove the used transmission fluid,
the pan should be removed also, and an inspection should be made of the pan
contents, fluid, and filter to determine the condition of the transmission. Aluminum
filings in the pan or iron filings on the pan magnet are signs of internal wear and may
give light to potential problems in the transmission. Transmission service is
performed for preventative maintenance. Evaluating the overall condition of the
transmission by removing the pan should be part of this preventative maintenance
also.

PR FIEBRU

Does anyone replace the tranny filter????

Or has anyone taken it out cleaned it and put it back.

Or does everyone just drain and flush?