This is something that I have often heard: %26quot;On higher mileage vehicles the transmission fluid is saturated with friction material from the clutches. Replacing this fluid with new fluid which contains new detergents can start the so called break-in process all over causing more clutch wear. So if you have an older car that is not leaking or consuming transmission fluid just leave it alone.%26quot; If this is the case then what is the best way to deal with this? Do you change half the fluid (leaving half new half old) along with the filter and gasket?|||Just change the fluid as described in the owner%26#039;s manual. The phrase is changing the fluid on OLDER vehicles. Older transmissions used mineral oil or Dextron (1). When used for long periods of time, they left a varnish coating in the oil passages. New fluid would break the varnish off where it would lodge in the shift valves causing problems. It did not help that when GM released the TH400, they said the fluid was good for 100,000 miles. Causing people to wait 10 years before changing the fluid. Most cars on the road use Dextron-II or better. This does not have the varnish problems unless you have repeat transmission overheating (towing). Some cars (Honda?) don%26#039;t even have tranny filters any more.
(a couple of side notes:) The fluid has multiple jobs, lubricating, cooling, hydraulic controls, cushion the shift changes, transfer power in the torque converter, and transferring power in the clutch packs. All trannys wear metal. It is found as the silver sludge in the pan that the repair shop shows you when telling you that you need a rebuild. Sludge (not broken parts) is normal The metal actually washes down into the pan, the filter stops it from being sucked back into the system. The metal is from the steel pressure plates of the clutches and drum metal, not the %26quot;friction material%26quot;. The friction material is PAPER !, which holds the fluid between the plates.|||Daily maint. is the key to a long life of the transmission.I did both. I didn%26#039;t change it because I waited to long and I also changed it. My Chevy truck had the turbo 300. They say that if you change it after sitting in the transmission that you flush out lose shavings of the transmission. Some trans have a magnet on the oil pan to catch such shavings. It is your call. But be sure they change the filter and gasket and also drain out the toque converter.|||Excellent question, but I wish I had the answer, I heard the same story from a mechanic. I had a car with 80K and changed the fluid and 2 months later the tranny went bad. Is that the fluid change or just an old car?.|||I never heard of that, U need 2 change the fuild at the first 100,000 miles.
Then change it out only if its is starting 2 turn brown. If it leaking, change out the gasket and filter.|||if the transmission had never been serviced before this is true. if the transmission was serviced at regular intervals this is not true.|||I have been working for 7 years in the repair industry doing a half dozen flushes a day and I have yet to see any evidence to back up such a claim|||if it ain%26#039;t broke don%26#039;t fix it.|||I am sure you have heard the saying, if it isn%26#039;t broke, don%26#039;t fix it. And, the same holds true, for a automatic transmission... If the transmission is working fine, the way it is, you are best off, leaving it be. Just stick to the normal business, of checking the fluid level, now and again. You need not worry, unless you see or feel a marked change in the transmission. If this arises, then, check into the problem, but not untill. If all is going smoothly, leave it be, till something goes wrong.
