Tip & How-To about Ford F-150
A basic rule of thumb for changing the trans fluid is two fold. Time and condition. As a lubricant it should be changed about every 2 years or about 30-36,000 miles. However, if your trans has a dipstick, you can check the condition of the fluid and determine if you have more or less time. The fluid should be red and clean. If it is black, sorry too late, if it is brown or brownish red, change it. If it is bright red, it is still good.
There are two methods of changing transmission fluid.
The first is to remove the pan and dump all fluid in the pan out, replace the filter and pan gasket and put it all back together and refill trans
There is a problem with this method. While a new filter may seem nice, it is not necessary unless the vehicle is quite old. The filter is there to keep very tiny wear particles from the transmission's internal components from reaching the valve body and causing a valve to hang up. If there is so much material in the pan that it blocks the filter, it is too late to change the fluid, you need an overhaul. Also when you use this method you only change about 50% of the fluid. There is fluid in the torque converter, cooling system and throughout the trans that is not changed.
The second method that I personally recommend for those who want to maintain your trans, (More less you are doing it because it is good maintenance and not because you suspect you have a problem) is a flush method. This process does take a little mechanical aptitude, but can be used on all types of automatic transmission.
First you find a cooler line coming from the trans to your radiator. either one is ok, pick the one that is easiest to get to. For those of you who want to do it the best way, look up and find which line is returning from the cooler back to the trans and unhook that one. Once you know what size the cooler line is, most are either 5/16th or 3/8's. You can pick up a short brake line at a parts store that will screw into the line hole in the radiator. At the same time that you get the brake line, buy a foot of fuel line that fits over the end of the brake line, You may need to bend the line to get it to fit, If you do not have a bender, just bend it a little at a time, just don't let it crimp closed. Screw the brake line and and attach a piece of hose to both lines so that you can catch the fluid as it comes out. Depending on the type of trans you will need between 8 to 15 quarts of fluid and a long neck funnel.
Once you have this all together, put the funnel in the dip stick tube, or remove the radiator type cap on the trans, and be ready to put in fluid. Start the car with the e brake on and in neutral. (if your car has an e-brake release out of part, do it in park, it is not a major difference.) As your fluid is being pumped out of the cooler line in to a catcher, slowly add fluid back into the trans. try to equal the amount to what is being pumped out. When you start seen fresh red fluid again. stop putting fluid in for approximately a quart worth of oil coming out and then shut the car off. reattach the cooler line into the radiator, start the car and check your fluid level. If you need to add fluid until it reaches the full mark, hot and running.
You just changed all your fluid.
Note, certain trans do not have a dip stick and while this procedure will work, you have to know where the plug is that comes off to check fluid level. Some of these models are GM mid size like Malibu, Mazda, Ford Explorers, BMW/s. These and I am sure others have a pipe plug that when you find it while the vehicle is running you fill the trans until you see fluid running out of the plug.
After all this, you understand why a shop will charge 100+120 to perform the service with a flush machine that cost them $5,000. But if you like working on your car, you can do it yourself and save about 60 bucks.
Submitted by Rich (autotherapist) with 28 years of transmission rebuilding and shop ownership in the transmissions field.
Posted by Rich ... on
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