On an automatic transmission After doing a drain and fill, if I want to do another drain and fill I know I have to mix the new fluids I just added with the old before draining it a second time. What's the best and quickest way to mix all of the fluids?

Is it enough to sit idle and just set the shifter to all of the gears? Or just drive around in D4 for one minute?

I've thought about doing the method where you hook a hose up to the cooling line and put new fluid in until the old fluid runs out clean but I don't know the rate at which to put fluid in to match the rate at which fluid goes out and I'm not sure what kind of damage I might do by running it dry.

 

I'd give it more than what you are suggesting. I'd drive it around for at least 20 miles. Letting the trans shift thru all of the gears and that. Then let it cool and go for the next change.

I've seen the video on the other method.....need two people (someone to shut the car off), plenty of fluid, tops already off ready to pour the next one just as the one empties.....thought I'd stick with the tried method of just drain and fill. Just my two cents on that.

 

Drain/fill is easiest no doubt, but mighty wasteful of precious ATF.

I've done the simultaneous pump out/install new fluid in intermittent approach. It takes a bit of hustle as the internal hydraulic pump rate is fairly high, perhaps 1-2 gpm. This means you only have seconds to start engine, check fluid level of catch pan, and stop engine. It would be helpful to have a partner, but I managed by myself. Refill reservoir w/ new fluid and repeat (5-7 times) till clean fluid is returned to the outlet. Trans fluid level is never over 1-2 qts low.

I used a clear plastic hose installed over end of trans cooling line hose to allow sight of the exiting trans fluid and know when clean fluid arrives.

good luck

 

Alright, I may try the cooling line method.

Is the cooling line always the one on the left? A video I watched shows it on the left of the two lines near the solenoid.

Is it safe to shut the engine off to "pause" the procedure? I plan on having a helper.

I am unsure whether the rate at which the funnel I am using allows fluid in is enough to satisfy the rate at which the fluid flows out, I'm not sure if it's safe to say that if the funnel isn't dry (let's say it's 3/4 filled with fluid and draining) that the transmission is also not dry. In other words if the transmission is full of fluid more than it allows, it wouldn't back up into the funnel, it would back up out of the dipstick hole that the funnel sits in and fall on the floor right? It's hard trying to strike a balance between not filling it too much and filling it enough so it's not running dry.

 

Check youtube video "10 min Atomatic Transmission Fluid Flush" w/ the mis-spelling. This is an Accord so it tells you where the correct hose to separate is located.

I used this as guide, but performed an intermittent drain/fill/drain/... rather than continuous operation in the video.

Rather than hope I was installing fluid faster than draining, I used the intermittent procedure to be sure there was always fluid in the reservoir (check w/ dipstick). Doing this solo, I had no choice.

It may help to mark 1 qt intervals on your catch pan to make it easier to know how much to install.

good luck

 

I did one drain and fill, then did another the next weekend. You should at least run the transmission through all the forward gears, plus reverse a few times. The flush method would take some planning.

 

Don't do the power flush, Honda recommends just a drain and fill, power flushes will screw up any auto trans ,