Tom

Dear    Tom,

Q I own a ‘96 Toyota Camry with 133,000 miles. The local Toyota dealer

says that it’s way overdue for a transmission flush, but when I go to local
quick lube shops they all refuse to do it because of the mileage on the
vehicle. The transmission operates perfectly now, but the transmission fluid
is a dark brown. Is it wise to have the dealer do the work and risk having
trouble after the job? Or should I just keep driving and hope for the best?

Mary—Washington,    D.C.

Mary,

A The answer to this question is a tough one. On high-mileage vehicles,

transmission fluid change is a crapshoot because one has no way of knowing
the extent of internal wear. When the old fluid is overheated it loses its
lubricating and cooling properties and, most important, its ability to act as a
hydraulic pressure medium. The transmission experiences excessive internal
wear. This wear causes the unit to heat up. Heat causes the rubber seals to
harden and the glue on the clutches to become brittle and crystallize. When
new fluid is introduced into the unit, the high detergency of the new fluid
scrubs the old glue away from the back of the clutches, rendering the
transmission useless. As for the rubber seals, the fluid leaks by them because
they have shrunken from the heat. Take it to the dealer and have the dealer
drop the pan to try to get a handle on the extent of internal wear before
flushing the transmission. Then you can make an informed decision on
whether to proceed with the flush. Good luck.