In our previous post we covered crank case engine oil, how to check it and what to look for. In this post we will cover checking transmission fluid and what to look for.
Next to engine oil, transmission oil is probably the next most important fluid. It is vital for automatic transmissions to have the proper level in order for them to operate correctly and have the transmission shift properly and ensure long life.
The first thing we do is go ahead and check the fluid level of the transmission. Locate the dip stick and pull it out without the vehicle running. Sometimes there are instructions on the dip stick on how to check the fluid. Also look in the owners manual if you have one available, the instructions should be located under fluids. Most manufacturers indicate that the vehicle should be warm, engine running and in neutral. Wipe off the dipstick and re-insert it and pull it out again and check that the fluid is in the recommended limits. Also smell the fluid, it should not have a burnt smell. Most transmissions should have a red tint to them also and not be totally black (this depends on how high the mileage is on the vehicle).
With some newer vehicles, the transmission is a totally sealed unit, meaning that you can not add nor even check the fluid. With these vehicles and vehicles that you can check alike, we recommend that you go ahead and drive the vehicle. If the vehicle is cold, while you are driving, notice if the vehicle is shifting smoothly. We like to do this two ways. One, from a complete stop, gently giving it more throttle as with normal driving conditions. Second, from a complete stop taking off harder and faster. The rpms will generally go a little higher before the engine shifts when testing this way. If you have the owner of the vehicle in the car you may want to let them know what you are doing before hand so they won’t have a heart attack and think you are trying to tear up their car. When a transmission is cold is one time when it will act up and not shift smoothly. Check to see if the rpms (engine revolutions per minute) are running high and the engine is working hard before the transmission shifts. Also when the vehicle is good and warm, take notice again of how the vehicle is shifting.
Changing transmission fluid isn’t something that is done as regularly done like changing the engine oil. However, it should be changed according to the manufacturers recommendations. This information should be listed in the owners manual, and hopefully the seller has one. We are not big fans of the systems that change the transmission fluid by taking it out by the fill tube. Some oil change places do this, and we have seen where having this done when a vehicle has 100,000 miles on it has done more harm than good. After having this done the vehicle will not shift properly. Always ask the owner if they have had the transmission serviced and how it was serviced and where. We recommend if the fluid is to be changed go ahead and drop the transmission pan and changing the filter.
Lastly, you always want to take a vehicle that you are considering purchasing to a certified mechanic to give it a once over before purchasing. You should also get a vehicle condition report to see if the vehicle has service records available from the dealer. When vehicles are serviced at the dealer they usually report it to the major vehicle condition report companies and helps keep record of all recorded services done to the vehicle.