Transmission fluid Exchange and Service DIY

Decided to do a simple writeup on a trans fluid exchange with a filter replacement. I didn’t really see one so I apologize if this has been done already.

To start, I do believe in “flushes” as opposed to drain and fills. To clarify, “the kinda “flush” I am speaking of is an exchange of transmission fluid not a powered machine flush, which I would not recommend. I used to work on this type of equipment and all other types of garage equipment, and these machines are not the most fool-proof. Not going to go into the particulars but I will say that some of the machines are much better than others. Being out of that business for 20 years I used to service the TTech machine which was a giant clear tube that essentially filled one side of the tube with the new fluid and the other side collected the old fluid. It used the pressure of the transmission pump, via the draining fluid collecting in one side of the tube to push the new fluid into the transmission. Pretty simple machine. No pumps at all. Other machines use pump and level transmitters that can get fouled up and be a problem.

All that being said, This exchange process is fairly easy. Unhook the return to transmission line and divert that flow into a bucket, collect and measure about 3 qts at a time, and replace with the same amount pumped back in. This is all done after the pan drain, filter replacement, and magnet cleaning. Details forthcoming.

Tools and items you will need:

1. At least 12 qts transmission fluid ( I would go for 13 or 14 as the factory fill is 11.7Qts)
2. Transmission pan gasket (OEM looks reusable so you might be able to clean and reuse) Toyota part # 35168-0C020
3. Filter Toyota part # 35330-0C030
4. Brake Kleen or Carb cleaner
5. 6 foot 3/8 hose (for attaching to return line)
6. 4 ft 3/8 Hose for attaching to pump to transmission fill hole
7. A 12V fluid pump (you can use a cheaper hand pump but it will give your hand and arm a workout) I used this

HighFree 12V 60W Portable Electric Oil Pump Extractor, Transfer Pump for Boat, Car, Motorcycle, Truck, RV, ATV

https://www.amazon.com/gp/product/B08243WC2H?ie=UTF8&th=1
8. 1 gallon graduated container ( to measure the drained fluid) OR mark the inside of your bucket
9. Larger drain pan
10. 10mm socket for transmission pan bolts and filter bolts
11. 12mm socket to remove cover on transmission shifter and plug
12. Allen for level check plug
13. New metal crush gaskets for the plugs
14. Pig mats (absorbent cloths)

First step is to drain the fluid the transmission fluid from the pan. Remove the 2 – 12mm bolts for the cover for the linkage. Then remove the fill plug. Using the correct size allen wrench, remove the level check plug the the green straw. I got out about 5 qts. Be aware that there is another qt or 2. I think I read somewhere that the pan holds about 6 qts which is about what I measured

Next, remove all the transmission bolts except for 2 on both short sides close to the middle. The idea here is to try not get fluid all over everything (and yourself) Loosen the bolt a little in the front with the drain pan underneath. I had the front up on ramps so the thinking was that more fluid would be towards the rear. Continue to undo the front bolt but do not remove it. This will act as a hinge point. If you get it loose enough there is almost no way you can bend the flange on the transmission pan but still be careful and use your hands to support the pan.

Once the front bolt is loose enough, start to undo the rear bolt. Have the pan underneath ready as fluid will certainly come out if it didn’t already come out when the front bolt was loosened. Continue loosening it until while supporting it and lowering it with your hand and tilting it a little bit to the driver’s side to pour fluid out. Eventually, you’ll get to a point where you have to undo the rear bolt completely. Just support the rear of the pan while taking out the rear bolt then gently and methodically lower the rear of the pan to drain more of the fluid out. Make sure you have enough play in the front bolt so the pan can pivot downward. You should be able to get out almost all the fluid without removing the front bolt. Next, just push the pan up, in the middle, against the transmission with one hand in the middle, and take out the front bolt and then lower the entire pan down and dump whatever is left into the drain pan. Shouldn't be much at all.

Keep the drain pan under the open transmission for a bit and while removing the filter which holds more fluid (about a ½ quart) Remove the 4 bolts holding the filter. Mine still stayed in place and needed just a light tug to remove but be aware that it might fall out once the last bolt is removed. When removing the filter, tilt it to the end to drain as much fluid as possible or just drop it in the pan and deal with it while not underneath the truck. The red o-ring should have come off with the filter. Just be aware if it didn’t. The new filter comes with an o-ring. Also take note of a little yellow tube on the transmission that can get pivoted one way or another. This goes up into the end of the filter. You will need to measure the amount of fluid you drained from the pan total. I got 5.5 quarts which is almost half the total capacity of the system.


To install the filter, gently push the filter into place until all the bolt holes line up and put the bolts back in. Try to get the first bolt all the way in, preferably one of the long side bolts, so things stay in place and lined up. Make sure the little yellow tube is in place. Torque to 7 ft/lbs.

If you haven't noticed by now, fluid continues to drip from various places. This runs down onto the mating surface in a couple places where the flange gasket will be. You can dab off the drips of fluid on the valve body and solenoids. You can also wipe off the gasket mating surface for later to be able to see where you need to pay attention when reinstalling the pan. Keep this in mind for reinstallation.

Service the pan. Remove the gasket and clean and prep for reuse OR install a new one once the pan is clean. Remove and clean the 4 magnets in the pan. There are little creases that show where these magnets go. The magnets also have a tiny bevel, on one side, that goes down and, to me, fit perfectly longwise between those creases. Clean the rest of the pan with brake clean and a lint-free paper towels and dry thoroughly. Wipe out the brake clean residue. Check the flange for any damage and repair, then press on the gasket. Make sure the level check tube is clean and damage free too. The pan is ready for installation.

Next, take the pan and can of brake fluid and go under truck. Chances are you will see where the fluid has run onto the transmission gasket mating surface again. Fold up a lint free paper towel and wet it with the brake fluid. Wipe the area and the rest of the mating surface and try to clean above where the flange is wet to give yourself some “drip” time to get the pan in place before fluid runs down onto the mating surface again. The idea is to keep both surfaces clean and dry.

Install bolts opposite one another so the pan is snug against the transmission. Use a socket on an extension or a nut driver to make this easier. Install the rest of bolts and snug up in a cross pattern starting in the middle on one of the long sides. Then go back and torque to 8 ft/lbs in same pattern. Reinstall the level check plug. The transmission is now ready for the next step of refilling the pan then exchanging the fluid.


Install at least a 4ft 3/8 hose in the fill hole. Enough to get it outside the truck into a bucket. It should fit snug in the fill hole of the transmission. Hook this to the output of your fluid pump out from underneath the truck just to make it easier. Open 6 qts oil and have them ready. Install hose on inlet of pump. Some of the hoses, tubing and the clamps hopefully came with the pump. Use them so hoses don’t pop off. Might have to get some jumper cables or rig something up to run the pump electrically. I used my jumper box. You can use a hand pump but be prepared for an achy hand when you are done. At this point you should have everything in front of you to systematically put 5.5qts in.

Now just pump in the 5.5-6 qts to fill the pan.

Next, get the truck ready for the exchange. First you need to pin the thermostat. Push the little ”button” in and stick a small allen wrench through both hole.




Next, undo the return hose and slip the longer 3/8 hose onto the metal end and into a 5 gal bucket. Normally this would be enough but some fluid trickled out of the hose end (going to the thermostat) during this process. Either put another hose on this and run it into the same bucket or just put a pan under the hose. Or maybe plug it somehow which, in hindsight I probably would have done because I believe I may have lost some of the new fluid I was pumping in at times, from this hose. Account for this when you are measuring.
I’ve done this process numerous times on other vehicles and the Tundra transmission pump is pretty low pressure but you still want to secure the hose to the bucket somehow, so it doesn’t kick out.




Now, by calculation, I figured I would do two rounds of 3 qts and the extra ½ qt to slightly overfill for the level check later. (5.5 + 6 + .5 =12 -11.7 capacity = .3 overfill) I also figured 3 qts would be good as the drain pan held over 5 and the suction of the transmission pump shouldn’t run dry. Start the truck and shift through the gears (obviously with the brakes applied) put it in park, then immediately go to the bucket and watch the flow. I eyeballed 3 qts and measured what I got out when I stopped the truck but if you wanted to put a little mark on the inside of the bucket for 3 qts that would make this a little easier. It took about 30-45 seconds to get 3qts.

Just a note, I left the hose in the fill hole when I started the truck as there was very little pressure in the pan.
Now pump the 1st round of the 3qts to refill the pan and replace what you just removed.

Repeat the process above and you should have a filled system.

At this point, you remove the hoses from the fill hole and the return line, put the plug back in the fill hole. Don’t put the cover back on as you might have to add more fluid. Now you have to do the fluid level check while warm. Also have to put the truck on level ground to do this. I missed my lifted Tacoma at this point LOL. I have Techstream which shows the transmission temp, which needs to be between 99-111 F. I don't recommend a temp gun. Carista maybe or a Scanguage? When it’s in that range you loosen the check plug and get it to a trickle. No trickle add more fluid. Reinstall the linkage cover. You are now done.

Thanks to KKK2023 for the pictures that were useful.
If anyone has any suggestion on how to make the DIY more useful or comprehensive, I'm open to suggestions. Hope this helps someone.

 

My plan is to simply remove the transmission pan bolt - catch what comes out, measure and replace with equal amount of new oem via the fill bolt hole - all at cold temps. Run for a week or so and repeat two more times. But not until I hit 30K. Your approach will hopefully yield you the intended result. Good job and write-up. Much appreciated.

 

Love it. Great write-up. Really appreciate it.

 

Thought we also had to get the fluid life reset via techstream?

 

Oh, didn't know about that. Please give me more details.

 

AKA another money grab from the Mothership. I don't doubt it at all.

 

Thanks, I did search and read up on that. I am somewhat skeptical that the transmission actually would increase pressure somehow if this isn't reset. At least that's what one person said in the thread I read and that thread was in the 2.5 gen thread. When I get home I will go through and reset mine. Not sure what people would do if they didn't have TechStream. I guess just go to the dealer. I got my Techstream on the interwebs by paying a few dollars and jumping through some "strange" hoops. Probably can't mention that stuff here but it is out there for anyone with any Google fu. I do appreciate the heads up though. I am new to the Tundra and willing to learn

EDIT: Here's the thread I read about the reset.

https://www.tundras.com/threads/5-7l-transmission-cooler-kits.60550/page-28#post-2293965

 

So what's the verdict on the filter in the pan, is it a real deal paper filter or is it just a course screen? Is it really worth dropping the pan to replace the filter?

 

it is a paper filter Looks just like a pleated air filter inside.

 

Coarse filter, to catch chunks of metal. It does not filter worn frictions. Not sense replacing it. It filters nothing in a good working transmission. Dying transmission you need to rebuild, not just replace the filter.

 

If Toyota is requesting that their own technicians do it, then you should probably do it.

 

Older Aisin transmission would switch to torque converter almost always locked up strategy if ATF degradation counter reaches some exorbitant value. In real life that always meant the transmission is FUBAR. Actually, transmission was usually unusable long before that happening. That said, never in my life I reset that degradation counter. Even after rebuilding transmission and installing a brand new valve body. The degradation counter is still whatever it is for the 275k/19 years old transmission Shifts like butter.

 

I did do it. Easy Peasy. I forgot to take note of what the value was before I reset it. Oh well. Didn't make any difference in how it shifted though but at least I have some sort of peace of mind

 

What was your mileage when you did the fluid change & what year Tundra? Thanks for the write up.

 

72K 2022

 

Nice thank you…you’ve put some miles on!

 

Bought it like that which was part of the reason I got it because it was beyond the highest motor failure mileage I had seen on here, runs like a top and was well maintained.

 

Yep, this is why I asked about the procedure...couldve sworn I saw something about resetting the degradation estimate

 

Anyone follow the Car Care Nut video on this procedure?

When it came time to do the N > D > N > D part, I never got a ATF light/Solid D indication on the dash.

I didn't use my scan tool but went by my radio which tells me trans temps. Went from about 60° to 125° before I gave up on the indicator light.

 

Btw, anyone know the part numbers for the gaskets? Need one for the drain and standpipe plug. TIA.

 

Transmission Oil Drain Plug - 90341-12034
Transmission Oil Drain Plug Gasket - 90430-12008
Transmission Oil Overflow Tube - 35125-34080
Transmission Oil Fill Plug - 90341-18059
Transmission Oil Fill Plug Gasket/Oring - 90301-18008
Transmission Oil Pan Gasket - 35168-0C020

 

Muchas gracias mi amigo