OK I finally decided to give something back to the net. I decided a few weeks ago to flush the transmissions on 2 cars. 2000 Toyota Avalon with 70K and 1997 Toyota Corolla with 120K. This was brought about by 2 things.
I tried to get the Corolla flushed at a local quick lube and they asked if it had ever been flushed before. It is my wife's car and she had it before we met so I didn't know. When I told them, they said they wouldn't flush it because it might mess up the transmission and they didn't need the grief.
2nd reason was I had changed the AT filter on the Avalon about 3 years ago and it has leaked ever since.Let me start with this. If you transmission isn't leaking DO NOT replace the filter. It isn't worth it. It is a real mess. If you insist on doing it I'll describe it later. JUST DON'T DO IT is my advice.
When I said I had replaced the filter before I knew what a mess it was going to be but I had created a leak that was getting worse. I torqued the pan bolts to spec in the recommended order but it leaked. I tightened the bolts but it didn't help.
1st a little background. Your automatic transmission has a pickup that takes fluid from the pan and draws it through a screen that acts like a filter. Then it goes to the torque converter is used in the fluid portion of the transmission. In this process it gets hot and needs to be cooled. So it comes out of the top of the transmission and gos to the radiator. After cooling it returns to the bottom of the transmission pan.We are going to disconnect the return line and let the transmission pump old fluid into a jug while we pour new fluid in the top.
Step 1) Get a clear/transparent 1gal jug. Milk jug or windshield washer work great.
Step 2) Mark 1Qt lines on the jug. I used a large measuring cup. I measured out a quart of water then poured it into jug and marked side. Repeat 4 times.
3) Find the tubing that connects the radiator to the AT pan. Get an idea of the size and go to home depot or lowes and buy some soft tubing that is about the same size. I bought 2 different sizes just to be sure.4) Drain AT pan. My cars both have a drain plug but I've read that not everyone is so lucky. If yours dosen't have a plug I'll give some suggestions later. When you drain the pan meausre how much you just took out using the jug you just marked. Mine took 4 qts but the full system is 8 qts. The rest is in the torque converter and in the radiator.
5) Put in new fluid to replace what you just took out + 1/2 to 1 quart additional. You have to fill AT fluid through the hole at the AT dip stick goes in. The reason for the extra is you don't want your transmission to ever be dry.6) Find the hose that comes from the radiator and goes to the bottom of the AT pan. This will be the return. If you disconnect it at the radiator just take the hose you bought and put it over the outlet. Make sure to have a drain pan to catch anything that drips.
7) Now you are ready to start. Open as many qts of AT fluid you think you will need. In my case I added 8 quarts total so I opened up3 qts and had them ready. Remember I put in 1 extra when I refilled. Put a funnel in the fill hole and get everything ready to pour.8) You'll need a friend for this. One of you will start the car and work it through the gears while your foot is on the break. This should open up all the valves in the transmission. When the engine starts running fluid will start to fill up the hose you connected. Put put the end of the hose in the marked jug. As you see fluid start to fill the jug start pouring the new fluid in. As it crosses the 1qt line you should have added your 1st qt. Do this until the fluid runs clean or you put in as much as you want. I only put in 8 quarts total because I bought synthetic for the Avalon and it cost $10 per qt. For the corolla I bought 2 gallons and poured them both through.
9) Make sure you put in as much total as you drained out. Then reconnect the hose and clean up. You just performed a $90 service for $20 -$30. If you can change your own oil you can do the flush is was pretty easy.If you don't have a drain plug. You have 2 choices. 1) Follow the instructions above just don't drain pan. You'll be mixing new fluid with the old fluid in the pan so it may take more fluid to run clean but anything is better than nothing. 2) Suck out the fluid through the fill hole. There are some systems out there for this.
Good luck. My next project is to replace the AC compressor on my mothers Honda. I'll post what I find if it works.