DIY: Full Flush for Automatic Transmission

The harbor freight pump doesn't screw on to the top of a 1 quart bottle, it has a tube that drops into a 1 gallon jug. I'd guess 8-10 strokes per quart. Funnel sounds like a good idea so long as you don't overfill. Of course a drain pan ought to be under there anyway on general principal so it might be simpler.

 

Awesome write up. I read all 19 pages including the 100 posts about trying to use suction, ha. I am about to do this on a 2006 V8 4runner w/ towing pkg @126k (sorry if 4runner talk is not allowed). I have done this a few times on the 3rd gens so besides the temp check and how to fill, it sounds pretty straight forward.

I like the idea of the sprayer, but I am a little confused. The OP says to hook up 3/8" ID hose to the RETURN line to pump OUT the ATF. The sprayer people have said they hooked up the sprayer to the RETURN line to pump IN the ATF.

Are people using the sprayer by unhooking and taking it off the return line to pump OUT ATF, then hooking the sprayer back up to the same line to pump IN ATF, all on the return line?

Also I am assuming according to Crom that this is happening at the towing package tranny cooler, not the radiator? Is 3/8" ID hose still good?

Thanks for all the good info. I am usually a lurker unless I really need some help.

 

Return line means the line with transmission fluid returning from the cooler to the transmission so effectively you're pumping fresh fluid into the tranny.

 

^This.

Good job on reading the whole thread! lol I don't remember exactly what type of vinyl tubing I used. I have all types in my garage. And yes it was done at the cooler. The sprayer method should work for trucks without the ATF cooler and using the lines that go to the radiator, but you would have to use hose barbs to attach. That's what I would do. Hope this helps!

 

3/8 ID I believe.

 

Thanks for the replies. I guess my question isn't clear. Both the OP and Crom have said they are using the return line, however the OP is using the return line to pump (using transmission pressure) the old fluid out and Crom is using the return to pump (using sprayer) new fluid in.

I can't see how this would work because lets say you pump out 2qts old fluid out the return line and then pump 2 qts new fluid back in the return line the next time you pump out the return line wouldn't you just be pumping out the new fluid you just put in?

I have to be missing something or people are using both lines for this?

 

See if this helps, if not maybe someone can say it simpler.

Disrupt the trans cooler service loop by disconnecting the input (in/hot), and the return line (out/cool). The in/out is from the perspective of the trans cooler NOT the transmission itself.

The out/cool return line is the hose that carries cooled fluid back to transmission.

The truck transmission pumps hot fluid through through the in/hot line which would normally go to the cooler, but you have broken the loop and now it's going into a catch bucket. Using a sprayer, you attach to the out/cool return line, and manually pump new fluid back into the transmission.

 

Perfect, thank you Crom.

So both lines disconnected at the cooler. See which one pumps out fluid and use that to drain. Other line gets sprayer and coolant pumped in.

 

You got it!

 

By "coolant" I'm hoping you mean ATF?

 

Wait I thought if you just use red liquid it works either way? J/K, yeah I meant ATF

 

good catch!

check my diagram below, I believe I got the flow direction correct after looking back a few posts.

 

Going to have to give a vote for the sprayer method. Didn't even bother touching the fill bolt or draining the pan first. Pumped out 2 qts at a time and ran 14 through it. Was overfilled maybe by a half a qt in the end.

Thanks for the great write up

 

Thank you very much for the write up.

My 2010 truck is at 68k. It was bothering me for a month or two now because I've been seeing conflicting information about when to change the transmission fluid. I don't drive my truck hard and have towed a boat about a dozen times. The shifting has been more noticeable in the last few months. I decided yesterday that the only way I'll stop worrying about it is to just do it. Boy was I glad that I did. At 68K, the fluid is dark brown / almost black, no burnt smell. I used Valvoline Maxlife based on the reviews I've read on here. Cost of the fluid was $80 for 4 gallons and $5 for 1/2" clear tubing. I used a fluid pump from Harbor Freight to fill the fluid through the fill bolt. Total time taken was 2.5hrs, but most of the time was spent doing the fluid level check. My truck shifts smooth like butter now, I don't feel the shifting at all. The hard 1-2 shift is now completely gone.

My advice for anyone looking to do this is to do it when your truck is completely cold. I did mine after driving home from work, even with all the old fluid flushed out and new fluid in, it was still too hot for the fluid level check. The minute I get it into temperature check mode, the light was blinking.

I used this Harbor Freight pump to get the fluid into the fill plug. In hind sight, I don't see why you can't use this same pump to pump fluid into the return line from the transmission cooler.

 

Awesome sauce! Great work, glad you got it changed out, thanks for taking the time to write your experience in the thread.

 

So you didn't do a 12 qt. flush? You drained and filled thru the fill plug at the top of the transmission? Did you repeat this process more than once?

 

Looking to install a after market cooler. In this diagram, is the cooler hooked up after the stock rad then tran cooler. Or before the stock cooler? Heard a lot of mixed reviews and just want to ensure I got it correct. Apparently the stock cooler is hooked up after the stock rad? Thanks for any help

 

It goes into the rad and then through the cooler. It goes into the top of the rad, out the bottom, then into the bottom of the cooler and out the top and back to the transmission.

 

I should of clarified.

This is what I did:
- Drain the pan and refilled with 3qts of new fluid.
- Disconnect the return line from the transmission cooler, slip the 1/2" clear hose onto the hard pipe, and routed the clear hose into a milk jug that's marked with 1qt increments.
- Had my brother start the truck while I watch the milk jug, and had him shut the truck off after 2 quarts drained into the milk jug.
- Open the fill plug and pump in 2 more quarts of new fluid.
- Had my brother start the truck up again until 2 more quart drained.
- Repeated the process until all old fluid was out and only new fluid was coming out into the milk jug.

After about 9-10 quarts, the fluid coming out was very red and clear. I could have stopped at 12quarts, but because I already opened the last gallon jug, I went for another 2 quart flush. I ended up using 14 quarts total and had 2 quarts left from the four 1 gallon jugs.

I bought my fluid at Autozone for $19.99 a gallon. Walmart was cheaper ($16.99), but it would have been a 1 1/2 - 2 hour drive in traffic, so I went with Autozone.

 

Awesome, heard a lot of mixed reviews and your the second to clarify for me. Appreciate it.