You do no have to believe what iI say about transmissions. After 40+ years as a garage owner I can tell you some specifics about hundreds of failed transmissions.
Flushing a transmiision with discolored fluid is an "iffy "service at best. The flush chemical loosens the deposits that have been resident in all the corner, cracks and pockets of the unit. This creates a debris field that will loosen when new fluid is added and within 5K or so miles will start to create transmission woes.
The torque converter cannot be drained unless you drill a hole and put in a bolt to seal the unit. (Ford has one built in) This leaves several quarts of transmisson fluid unchanged. Flushing is often a "gimic" transmission shops use to sell an over haul. Read the fine print on the work order and it relieves them of all liability.
The act of flushing loosens deposits on all the internal working components especially the bands and valve body. These loosened deposits get in the valve body chambers and the flush fluid often distorts the small plastic balls that chamber fluid to the correct band assembly. I have seen bands come apart as they are held together in many cases by burned material.
Internally the transmission has a plethera of working parts including seals, O rings, gaskets and most important the bands. Every time a transmission shifts a minor amount of slippage occurs. This happens so the driver doesn't feel a jerk when the gears change.
Most all transmission experts will tell you that the dark deposits are from the internal parts of the transmission and torgue converter that have been loosened by an additive. Oil change and most surely from a flush.
Remember your torgue converter also has a clutch that locks up giving you a 200 to 300 RPM drop and acts as an over drive. It is a very dark color and a little bit of debris goes a long way to discolor fluid.
Sadly the only way your problem can be corrected is to rebuild your transmission. I tell every one with a 2500 or larger vehicle to insure they have an aux transmisison oil color because heat is the real killer of most of the transmision problems as well as failure to service the units.
Sir; you are not alone in you transmission problems with forgetting to service a unit or expecting a magic bullet to cure everything when a high mileage unit is serviced.
Believe or don't believe what I have written, as a I am passing along facts based on my experience and beliefs. You are the end decision maker and very good luck to you.
Friday, May 19th, 2006 AT 8:19 AM