Anybody have a procedure to flush an automatic trans? Also, what is a good synthetic trans fluid to use? Thanks

 

I post that few days ago in this forum...

I use redline syn ATF.

 

Am I wrong or don't you need some kind of equipment to do a full tranny flush? I was told in a normal change only about 60% of the fluid actually gets changed, the rest is still in the tranny somewhere. And to do a true 100% full flush you need some sort of equipment to force the fluid through the transmission, using suction or air pressure I guess. Is this right or is it actually a DIY job?

 

Just do a drain and fill. Its easy and no fuss. YOu get a third of the tranny oil out and then fill with a synthic, I like mobile's.

If you have synthic motor oil, then you'll being changing that at 6k miles, just do the drain and fill on the tranny at the same time. I found that after two of these, drain and fills, my wifes tranny fluid was a perfect color.

 

Hmmm...something's a little wrong with that math!

 

Yep, that's the easiest way. Drain and fill...drive around for a week...drain and fill...drive around for a week...and if you want...drain and fill one more time. Easy to do.

Even my mechanic recommends this method over a flush.

 

That's a lot of synthetic fluid to go through, it is not cheap...

 

Some one in org posted a interesting flush method by using the inlet and outlet to the trans radiator. Someone correct me on this but it had to do with taking off the both lines and placing the infeed into a bucket of new fluid and the out let into an empty bucket and then turn on the car.

 

Come on. Cut me some slack, I was a maths major. Any who, it works out that two flushes will be fine. That's assuming ( and I shouldn't ***-ume nothing) that you haven't let the car get to the point of no return. So I suppose if you've never touched or thought about the tranny oil, and then look down to see black tar on the end-o-the stick. Then my two drain/fills won't be sufficient, necessarily so.

 

I think when it comes time for me to do this, I'll just pay a shop to do a 100% flush the right way. The problem with pouring it in a little at a time, besides taking a month instead of an hour or two to do, is that you're never going to get totally flushed. Each time you pour a little bit of new fluid in it just gets contaminated by the old stuff. You wouldn't change your oil this way would you?

 

Not too much more.

Automatic transmission fluid capacity (with the torque converter) is 9 quarts. A regular drain gets out between 3 to 4.5 quarts. So if you do three drain-fill-drives, at most it'll cost you another 4 extra quarts or so. Not so bad.

 

Uh...actually the full ATF capacity is 12 quarts, and I have found about 6 to 8 quarts on a drain and fill method that was in my pan. Of course everytime I take the drain pan off so there is a little more.

As far as the DIY flush method you would disconnect the return line from your AT radiator going back to your transmission. This is something you need a friend to help you with. Have your friend start the car. At this point you will see fluid coming out the return line. Fill the tranny as close to the same rate as the fluid coming out the return line. At the same time have your friend shift through all the gears stopping about 20 seconds in each gear. Have your friend keep cycling the tranny like this until you are done. You know you are done when you see clean, fresh fluid coming out the return line.

This is the most effective way to flush your auto tranny at home. Of course you have to be very careful in making sure you don't run the damn thing dry. But other than that it's really easy.

Good luck...

 

be careful, the fluid comes out fast? Have a hose in a bucket or so or you will get splashed

 

man i would recommend u to get your flush by a professional and do it right... i wouldnt flush it my self.... if u look around u could get a flush for like a 100 bucks..

 

professional, usually not! most of them is just some kid working a machine, they don't pay the big bux to do fluid changes. Just do a drain and fill on a regular basis.

 

TheMax has it! Couldn't agree more.

A friend of mine worked as a mechenic and the stories he had would cause the hair on my neck to stand up straight. And he had actual formal training, just think about the grease monkey in the pit making min wage.

 

is it really worth changin the fluid in my auto tranny to synthetic stuff? i've considered it, but i cant see that it would make a noticable difference. maybe make the tranny run a lil smoother and last longer???