8th Generation Honda Civic Forum - View Single Post

mike_si_29 · 04-17-2008, 01:35 PM

Hi guys,
I just found a cool article about how to flush automatic transmission fluid. I bet some of you know it already but just in case it will help somebody. I have SI but my parents and gf have auto. I really didnt want to take it to the shop to do it so i looked it up in Internet. It's for a Avalon, but the basic idea is the same for the Civic. Looks pretty straigh forward:

DIY Toyota Avalon Automatic Transmission Flush - CarSpace Automotive Forums

It's fairly easy if you have a garage and basic tools. I bought the Dextron III fluid at WalMart. I found that my model Avalon only has a screen as a filter, so I decided not to remove the pan. I had the car on those drive-up ramps while doing this.

1. I drained the tranny pan, refilled it with new fluid and replaced the plug.

2. I then removed the tranny return line from the radiator and stuck about 6' of clear 3/8" tubing on there as a return line. The return line then ran into a large container off to the side to hold the old fluid. Use a clear container with quart marks so you can watch it and keep track of how much is coming out. I used a clear 4 gallon cooking oil container. I guess a gallon milk jug could work too. Make sure it won't tip over as it is filling.

The radiator return line on my Avalon is at the bottom of the radiator on the driver's side. Or, if you lift the hood it will be the tranny line on the right as you are looking down. You need to remove the cover plate from under the car to access that area. Have patience, the hose clips and line can be a pain to get off.

3. I then removed the tranny dipstick and put a tranny fluid funnel in there. Then, with the help of my sexy assistant, I started the car. The tranny will pump the old fluid out and into the container from the exit line. It comes out as a full stream but with not a lot of pressure. It only takes about 30 seconds for a few quarts to come out. I wouldn't do it without an assistant to start and stop the car as you are watching it come out and pouring new fluid in.

As the car is running, you need to pour new fluid in the filler tube as the old is being pushed out. Do a few quarts at a time at about the same rate as what is being pumped out.

Eventually the fluid will be coming out clear which means all the old fluid is out. You need to buy a few more quarts than what the tranny holds.

So...You are basically pouring fresh tranny fluid in the filler tube while the old tranny fluid is being pushed out through the hose you attached to the radiator return line, and this flushes the whole system...get it? That's exactly how it works at the tranny shop for $110 + dollars.

I used 15 quarts of Penzoil Dextron III. Be careful and don't overfill it. Later check the fluid level several times on level ground as described in the owner manual. It's better to add a quart than having to drain one.

04-17-2008, 01:35 PM	#1 (permalink)
mike_si_29 Senior Member Join Date: Jan 2007 Location: Thousand Oaks, CA Posts: 414 Mike iTrader: 5 / 100%	DIY: Automatic Transmission Flush Hi guys, I just found a cool article about how to flush automatic transmission fluid. I bet some of you know it already but just in case it will help somebody. I have SI but my parents and gf have auto. I really didnt want to take it to the shop to do it so i looked it up in Internet. It's for a Avalon, but the basic idea is the same for the Civic. Looks pretty straigh forward: DIY Toyota Avalon Automatic Transmission Flush - CarSpace Automotive Forums It's fairly easy if you have a garage and basic tools. I bought the Dextron III fluid at WalMart. I found that my model Avalon only has a screen as a filter, so I decided not to remove the pan. I had the car on those drive-up ramps while doing this. 1. I drained the tranny pan, refilled it with new fluid and replaced the plug. 2. I then removed the tranny return line from the radiator and stuck about 6' of clear 3/8" tubing on there as a return line. The return line then ran into a large container off to the side to hold the old fluid. Use a clear container with quart marks so you can watch it and keep track of how much is coming out. I used a clear 4 gallon cooking oil container. I guess a gallon milk jug could work too. Make sure it won't tip over as it is filling. The radiator return line on my Avalon is at the bottom of the radiator on the driver's side. Or, if you lift the hood it will be the tranny line on the right as you are looking down. You need to remove the cover plate from under the car to access that area. Have patience, the hose clips and line can be a pain to get off. 3. I then removed the tranny dipstick and put a tranny fluid funnel in there. Then, with the help of my sexy assistant, I started the car. The tranny will pump the old fluid out and into the container from the exit line. It comes out as a full stream but with not a lot of pressure. It only takes about 30 seconds for a few quarts to come out. I wouldn't do it without an assistant to start and stop the car as you are watching it come out and pouring new fluid in. As the car is running, you need to pour new fluid in the filler tube as the old is being pushed out. Do a few quarts at a time at about the same rate as what is being pumped out. Eventually the fluid will be coming out clear which means all the old fluid is out. You need to buy a few more quarts than what the tranny holds. So...You are basically pouring fresh tranny fluid in the filler tube while the old tranny fluid is being pushed out through the hose you attached to the radiator return line, and this flushes the whole system...get it? That's exactly how it works at the tranny shop for $110 + dollars. I used 15 quarts of Penzoil Dextron III. Be careful and don't overfill it. Later check the fluid level several times on level ground as described in the owner manual. It's better to add a quart than having to drain one.