If your Mazda 626 transmission will not engage particular gears, or is having delayed shifting, you may have a serious transmission problem than needs attention from a professional mechanic. However, you may be able to save a little time and money, as well as fix the problem yourself, by doing some basic transmission maintenance before taking your Mazda into the shop. Do-it-yourselfers are basically limited to replacing the transmission filter and draining and replacing the transmission fluid for automatic transmission troubleshooting.
Turn on your Mazda 626 and allow the engine and the transmission to warm up. Watch the RPM (revolutions per minute) gauge for the ending of the warm up period, which is indicated by the gauge leveling out between 400 to 800 RPMs. Open the hood on your vehicle. Remove the transmission dipstick while the engine is still running and wipe it clean with a cloth. Insert the dipstick back into the dipstick tube and pull it out again. If the level is low, indicated by the transmission fluid level being below the minimum line or the bottom dot on the dipstick, add more transmission fluid via a funnel attached to the dipstick tube.
Inspect the color and odor of the transmission fluid. If the color is dark black, as opposed to a bright red color, then the fluid is old and needs to be changed. Smell the transmission fluid. If it smells like burnt toast, this is also an indication that it needs to be changed. Draining and refilling the transmission fluid may or may not improve your transmission's shifting on your 626, depending on what the problem is with the transmission.
Lift the Mazda 626 using a floor jack placed underneath the middle of the engine. Place jack stands underneath the reinforced frame sections below the front driver and passenger doors and place the drain pan underneath the transmission pan. Unscrew the drain plug from the transmission pan and allow all of the automatic transmission fluid to drain.
Use a socket wrench to unscrew the mounting bolts for the transmission drain pan. Clean the inside of the drain pan with a cloth and automotive solvent cleaner. Wipe down the magnets inside the pan. Use a socket wrench to unscrew the bolt connecting the transmission filter and replace it with a new one. Reassemble the drain pan and plug and add more transmission fluid using the funnel attached to the dipstick tube method described earlier.
Lower your Mazda from the jack stands and floor jack. Drive your Mazda 626 around the block, observing for any roughness or delay in the shifting of gears that are completely unavailable. If you continue to have transmission problems, a professional mechanic who specializes in transmission rebuilding and replacement should take a look at your 626.
