Transmission Fluid Change Question

To those of you who do your own maintenance cause you trust the dealerships just like me, not one F&%K&%G bit, how much are you getting out of the transmission pan with just the most basic drain and fill? I thought I read about 4 quarts. So lets get this straight or please tell me what I'm doing wrong.
1. Drain Fluid 4qts of 12qt system = 33% all old. Replace 4qts new. Transmission has 8qts of old and 4qts of new fluid in it. Drive truck few days.

2. Drain Fluid 4qts of 12qt system = 33% old and 33% new just got changed. Replace 4qts new. So after 1st change 8qts is still old so after 2nd change we changed 33% of that
8qts. Were now at 5.3qts still old in system. Drive around few days.

3. Drain Fluid. We just changed 33% of the 5.3qts of old fluid left but also 33% of the 6.7qts new fluid. Now were at 3.5qts of old fluid still in system.
This seems like a good place for about $120 in a case of fluid and since going further your not getting much result.
4. Drain Fluid = 2.3qts old left.
5. Drain Fluid = 1.5qts old left.
I understand I can drop the pan and that gets me about 6qts total but kinda pain in the arse when two drain and fills gets slightly better numbers. Again, my question is am I completely getting my numbers wrong or is this just how it is. My issue is the people who preach and say to play it safe and drain and fill every 30K really are not doing much or are most people doing a couple of changes each time?

 

That sounds like a lot of work time and money. I took my 07 to dealer and had them flush tranny. End of story.

 

Removing the pan is usually problematic due to pan bolts snapping off. That's why most owners recommend the drain and fill method. Personally, I'm not a fan of the drain and fill method, but understand why owners default to that choice. You can make your own decision on that.

You don't indicate what model year, what engine, or if you have the transmission fluid cooler. If you fix 737s, you will understand the risks, but should have plenty of mechanical smarts to change 100% of your fluid as in this video for the 5.7L. Ignore the intro pic with the manual gearbox, it's irrelevant to the video. This method should work for any MY with a transmission fluid cooler, and probably can be improvised for a 4.6L without the cooler:

https://www.youtube.com/watch?v=fLVZSoKbyZ0

I would caution against running the transmission pump below the fluid level; i.e. breaking suction and sucking air. Better to keep your valve body and other components completely fluid-filled. Drain the pan completely (measure drained fluid), and overfill transmission with fresh fluid by one quart. Then, start the engine and pump out two measured quarts. Shut off the engine, add two quarts, then repeat until fluid runs clean and clear red. Adjust the final fluid level as required.

 

Is the hole big enough to stick a siphon in it and suck out the fluid from the pan? Maybe stick it through the fill hole and angle it down.

 

I did drain and filled 3 times. It drains just about 4 litres each time. I did it when truck was cold and put back exactly what I drained. It's very simple.

 

Yes, but sucking the fluid out of the pan accomplishes little more than simply removing the drain plug. A suction pump may allow you to remove a few more ounces in the low points, but that's it. Changing the fluid in the torque converter and upper transmission is really the objective of the video.

 

That makes sense. I was thinking siphon vs dropping the pan.

 

Can you take your truck to the dealer with your own fluid......I am an amsoil guy but hard to trust they would use it. I really want to get this done but don't know where to go.

 

If you don’t really trust them, go somewhere else. Find a trans shop with a good rep in you area.

 

Clean up using a suction pump to remove all possible fluid could a good idea if not removing the pan. I would have to control my OCD, and skip it. There will be some minor contamination from the fluid residue in the pan, but there will be other contamination from the interior film adhering to everything. So, maybe only 99% fluid replacement is accomplished.

If attempting the suction, I would use the drain hole or level check port, and skip the fill hole. I know the fill port is big enough in diameter (typical Chinese pump suction line is <=6mm). I've inserted a 3/8" tube several inches into the fill port for adding fluid, but to reach the pan through the fill port may require threading the tube past the valve body, wiring harnesses, solenoids, etc. I would be concerned that the suction tube might somehow get snarled on some of that stuff. Then, you're forced to drop the pan, and endure the consequences, to remove the tube.

 

I’ve “exchanged” trans fluid on many Toyota’s now, and IMO the best way to do it is an exchange through the cooler lines up front. Whether you have a trans cooler or just the stock fluid pass through in the radiator, there are 2 lines that run to the front of the truck.

Simple How To:
Find the trans fluid lines that are right behind the radiator. There should be two hard lines that hook up to soft lines. Disconnect one of these lines and hook up your own tubing to both the hard line and soft line. Route your tubing into a bucket with premeasured quart lines.

Find the trans fill plug on the transmission. Usually towards the rear of the trans on one side. 24mm plug. Route a filler hose from the engine bay down to this filler port.

Start the engine and let it run for ~20 seconds. This should get you about 2 quarts and keep you above the suction line of the trans. Go back and fill the trans with the amount you just took out. Repeat until fluid runs red, usually takes close to 12 quarts. During one of the 20 second startups, run the shifter through each gear for about 3 seconds.

Take the trans up to the specified temp and pull the overflow plug to ensure proper level.

This ensures all the fluid is exchanged under the transmissions own power and there’s no dropping of the pan or even cracking of the drain plug. Every pan I’ve pulled on a Toyota, I wish I hadn’t because there is never any material to warrant concern and you usually break some bolts.

I’ve used this method on many Toyota transmissions with 100% success.

 

The cooler line method is easy. Did on my Tundra at 85k when I bought it, and did it on a Dodge Ram prior to that.

 

Thanks for the responses. My truck is 2019 so not in a hurry but just curious. Unfortunately its the non-cooler Toyota embarrassment so the nice trick of pinning the heater/cooler thermostat flush is ruined. Just wondered what most people do? Having the dealer do a flush is out for several reasons.
1. They literally do nothing and charge you for it.
2. They do it and put in wrong fluid.
3. They do it and over or underfill the transmission. If you SERIOUSLY believe for one second ANY Toyota mechanic on the planet will do final drain by waiting for the proper temperature then your insane. A flat rate paid mechanic has NO reason to wait when he can move on to next job and get paid again.
4. They do everything 100% by the book and everything is perfect. In my head I will always think 1-3 happened so for piece-of-mind do your own work.
I've done the proper drain and fill on several Toyota's and while daunting the first time its actually very easy. Especially with apps now like OBD Fusion you can have your phone in front of your face and see exactly when final drain temp is achieved. Except in Phoenix summer when waiting for tranny fluid to ever get below proper temp. is forever. Again, thanks all for the responses.

 

Dont understand why people get so hurt at dealership if they put wrong fluid over fill under fill and you have issues they are liable and will fix

 

I may be wrong, but even if your tundra didn’t come with the trans cooler, it should still have lines going up to the heat exchanger in the radiator.

 

2019+ do not have the lines or thermostat.

 

FWIW, I have a service department that I trust.

At my 35k oil change I had them also do the drain and fill on my '18.

They charged $90 to do it and that included 3.5 quarts of WS which is what I expected them to get out of it.

I'll do it again two more times at the next oil changes and call it good for a while.

Maybe it's a good thing, maybe I'm wasting my cash. Regardless, the fluid will certainly be in better condition than if I did nothing and I tow 7500# occasionally.

 

How are people adding external coolers if there aren’t any lines?

 

They are adding the thermostat and lines themselves. This has the list of all the parts needed including the Toyota lines.

https://www.tundras.com/threads/2019-transmission-cooler-kit.60550/

 

The warmer cooler has lines coming off them, I wonder what they do?

 

Nothing

 

they are part of the engine coolent system, so they take hot coolent from the engine block send it through the puck and then returns the coolent back to the radiator.

 

Thank you, I’ll head back to the first gen section now

 

Thanks much Dirt Dawg. Ran over this in my head and seems fantastic. Guess the only issue is making sure not to break suction. Very nice.

 

LOL​

 

What fluid do I need? Thanks!

 

Toyota WS