THE LOW COST FIX MAY COST YOU MORE IN THE LONG RUN What appears to be least costly quick-fix for any automatic transmission owner, is to simply have his or her fluid evacuated without dropping the pan from your local quick lube shop. Major manufacturers recommend that you replace your transmission filter every 15 to 30 thousand miles. They are encouraging you to have the old fluid drawn out, without dropping the pan and changing the transmission filter. Let's examine the positive and negative attributes of this idea. Transmission pan is dirty with metal and other contaminants.
Filter is likely to be clogged.
No opportunity to check for other transmission problems. No opportunity to check and repair leaks. Merely drawing out the fluid cannot completely remove the dirty oil from the transmission. Removing the pan allows for it to be cleaned and for the old fluid to be completely drained. Newer transmissions have a low flow of fluid.