by Bob Belding

So you have a vehicle that you are proud to say has had regular oil changes. You have maintained it to a “T”.

Or have you?

Automatic transmissionHave you ever changed your automatic transmission oil? Did you even know your automatic transmission has an oil filter?

Most people, even “Do-It-Yourselfers,” seem to forget their automatic transmission needs service and, if you leave it long enough, eventually the only feature on your automatic transmission that will work will be park!

To service the transmission you will need to go to a local auto parts retailer and purchase an automatic transmission filter kit for the make and model of your vehicle. You will also need automatic transmission oil for your vehicle and I would recommend using the exact same oil the dealer would use. If you use an equivalent aftermarket type oil, you may notice a difference in shift quality.

Servicing the automatic transmission is fairly easy depending on the make and model of your vehicle. Most import vehicles have a drain plug on the transmission pan which enables you to drain the oil before removing the pan from the transmission. Most domestic vehicles do not have this option, so you first have to go to your closet and put on the oldest out of date clothes you have because its going to be messy!

location of the filter
If you can drain the oil, do it, then remove all the mounting bolts holding the transmission oil pan to the transmission. Once the pan is removed you will see the transmission oil filter. On most import vehicles the filter will be mounted to the valve body of the transmission with mounting bolts. You will need to remove them to remove the filter. On most domestic vehicles the filter may be held to the valve body with a rubber grommet and retaining clip. Just slide the filter away from the clip and pull it down carefully.

You will be able to recognize the filter by looking at the filter in you filter kit you purchased. Your filter kit may come with instructions, so don’t throw them away. You may actually find them useful for torque specifications for the filter.

Now that the new filter is installed, you will need to clean the transmission pan completely and clean the area on the transmission where the pan is mounted. If the transmission pan originally had a gasket, it should be replaced by a gasket – NOT silicone!!

Make sure the gasket surfaces are totally clean or you may end up with
a leak and to fix it you would have to do this procedure all over again.

Placement of the magnetWhen cleaning the transmission pan you will notice inside of it a magnet. Remove the magnet and clean it thoroughly, then put it back in the pan in the same location. don’t use if to hang a picture of your hotrod on your tool box! The magnet helps keep the transmission fluid free of metal debris. Make sure you put it back in the pan.

Reinstalling the pan
Once the pan is clean, I recommend using an adhesive type glue to hold the gasket in place on the transmission pan. This will make installing the transmission pan easy. Start each mounting bolt by hand then tighten to specification. If you don’t have torque specs ask the parts retailer or dealer for them. Make sure you torque them properly. This will prevent leaking.

Fill the automatic transmission to recommended level and always check the level with the vehicle in neutral and at operating temperature. Don’t forget to apply the parking brake while doing this!

You should have your old oil and filter disposed of properly after this service. A service manual always helps when performing this kind of service yourself and a proper floor jack and jack stands are required.

If you do not have these items, I strongly recommend you bring your
vehicle to your trusted licensed technician. At a repair shop this service normally costs an hour’s labour plus parts.

This service should be performed every 50,000 kilometres as preventative maintenance. This will be money well spent.

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