2017 Lexus LX570 ATF Replacement (1 Viewer)

[RangerPepe]

Guys I am new at this forum and would like to share my story of complete ATF replacement in my 2017 Lexus LX 570 with 53k Florida miles.

Although the procedure is very similar to the one described in this thread Complete Transmission Flush DIY - VIDEO - https://forum.ih8mud.com/threads/complete-transmission-flush-diy-video.988261/ (Thank you @NLScooby for the video) there are some differences that Lexus owners may find useful.

For the fluid replacement I bought 3,5 gallons (14qt) of AmsOIL Fuel-Efficient Synthetic ATF. They have 2.5 gallon and 1 gallon jugs.

I took a short 15 minutes ride to warm the things up a little bit and set up the vehicle in the garage to be level at the frame, I had to remove left and right fender splash shields (3 10mm bolts at 15Nm and 2 screws on each) all the skid plates (10 bolts on engine cover @1 and 2 bolts on engine cover #2 - 12mm bolts at 29nm) and transmission pan protector assembly (4 bolts 14mm at 50Nm) in order to get to the transmission pan.

After removing transmission case cover (this is a black plastic cover on the transmission case on the driver’s side, use 12mm wrench because access is obstructed by the front driveshaft) and fill plug (27mm at 39Nm) I removed drain plug and small plastic overflow tube both were 5mm hex. For the drain plug torque is 16Nm for the overflow tube is super low basically stop when you fill it is in all the way.

Initially I didn’t want to drop the pan but after the pan drain I decided to do so to clean up the pan and magnets (4 of them) at the bottom of the pan.

I drained around 3,25 litter of ATF with the drain plug and overflow plug out. Fluid was blackish with a bit of burnt scent.

Transmission pan had also almost 1.3 litter of ATF in. Pan bottom and magnets where covered in the fine metal dust and a bit of sludge.

I then installed an overflow tube and drain plug back and cleaned up the pan gasket and transmission case pan housing with alcohol for it to be clean and DRY. Installed the pan on transmission case. I was able to find just a torque spec for the pan bolts but didn’t find any sequence for installation procedure. Below is the sequence I used for bolts installation and torque. (First bolt on hand tight (be easy here) then torque to spec (7.5 Nm).

Using fill hole on the transmission case I have added 5.5 qts of fresh ATF. And installed fill plug without tightening it all the way.

Initially I was going to drain ATF from the auxiliary transmission cooler and add fresh fluid at the same point at the same time using 2 buckets connected with PVC hose with airtight lids. But new thermostat type or thermostat valve ruined these plans.

It appears 2017 Lexus LX570 does not have a mechanical thermostat anymore that you can just press in and block with the paper clip as shown in the NLScoobys video. Instead ATF return coolant line has an electrical valve installed that blocks the flow when AT is cold. (see picture below). Luckily the return line still allows ATF to be drained out form the transmission. But unlike NLScoobys video fluid drained not from the radiator end but from the top hoses end. (see picture below).

Using access point at the auxiliary cooler I was able to drain old ATF and was adding new ATF using fill plug at the case. When draining the ATF be careful as the flow was pretty strong and fluid was draining fast. My procedure was to start the engine and cycle AT thru Reverse -> N -> Drive to S (S4 -> S3 –> S2 -> S1 -> S2 -> S3 –> S4 -> S5 -> S6 ->S7 -> S8) -> Drive -> N -> Reverse -> Park turn the engine off. And that was draining around 2.5 QT at a time. After each drain, I was adding the same amount back. Not once I have seen bubbles in the drain hose. Did it 4 times till all the fresh ATF have been spent.

ATF Level Adjustment

I did fluid adjustment using OBD2 terminals jumping method. Worked pretty much as described in Toyota TIS or NLScooby’s video. Jus want to mention please do not forget to disconnect terminals after D indicator disappeared for 2 seconds and you moved the shift lever to park and released the brake pedal. After you move shift lever to Park you will NOT see P symbol on the dashboard. Keep idling the vehicle till the D appears and quickly drain the excess of fluid out. (I took me good 5 minutes of idling to see the ‘D’ on the dashboard.)

I had around 500ml of fluid drain as excess.

After you install you drain plug and shut the engine off, torque fill and drain plugs to spec and do all the installation of skid plates and transmission case cover. (Don’t forget transmission case cover I did and had to do everything twice).

And that was it. Overall, I recommend to by a really nice hand pump for the ATF. I was using Walmart transfer pump with a suction cup and that one was taking and hour to transfer a gallon of ATF.

After the ATF replacement I can say that the car drives and shifts much smoother than before. Now I can even tolerate 1st to 2nd gear jerk when coasting at low speed. I think Toyota WS fluid is garbage and cannot be ‘lifelong’ or even long-term fluid. I would say WS fluid should have been replaced at 50k or at least one drain and fill at 30k miles. AmsOIL SS ATF seems to be nice, but it is too early to judge. Will do drain and fill after 30k miles and see how it looks. Below are some photos of the old fluid from the drain pan.

 

[TLC2013]

Thanks for the write up. Been studying up on the atf exhange procedure and tips from @NLScooby thread. Also switching to the AMSOIL SS ATF, just waiting on the the parts and fluid to arrive.

 

[04UZJ100]

WS fluid is certainly not garbage based on its 17 year tenure in service now. I typically recommended against anything other than OEM fluid, especially on something like the trans.

Great write up nonetheless.

 

[RangerPepe]

@TLC2013 No problem, I just wanted to add something to the community, as I did find a lot of useful info here while bringing my car up to maintenance baseline. Let me know if you face some specifics that I missed in my write up.

@04UZJ100 I might have made a bold statement regarding WS fluid. It is not flat out bad, more like good enough for the application. My gripe here was more about Toyota claim regarding WS been a "lifetime fluid" that does not require replacement (Which I call a BS). I definitely would NOT put the drained stuff back in transmission and leave it there for another 5 years.

Going for OEM fluids is a way to go for most of the people as long as using incorrect (incompatible) fluid will eventually lead to catastrophic failures of very expensive components. But what turned me off from Toyota WS was its conventional base. And comparing conventional vs synthetic was no brainier for me. Synthetics will always have higher thermal stability and wear resistance. Amsoil just happened to be one of the compatible synthetic fluids. I would say with more realistic maintenance intervals ANY OEM or compatible fluid will do the job really good. I did Amsoil in both differentials and power steering system, did Prestone Dot 3 (Walmart stuff) brake fluid and only used Toyotas fluids for AHC system and transfer case because there are really no compatible analogs. So far transmission shifts noticeable better and smoother, although I thought 50k mileage was too low to see any changes in transmission behavior.

The same way I don't run Toyota engine oil for 10k miles and used Motul 0W20 for my last oil change, that I will drain after 5k miles and then even switch to Pennzoil Ultra Platinum Full Synthetic 5W30 (for 5K intervals in the future. Because I don't understand why the same engine (or similar ones) in different regions (UAE) and previous years are totally fine with 5W30 and in 2021 in US call for 0W20.

 

[Hokie99]

@TLC2013 No problem, I just wanted to add something to the community, as I did find a lot of useful info here while bringing my car up to maintenance baseline. Let me know if you face some specifics that I missed in my write up.

@04UZJ100 I might have made a bold statement regarding WS fluid. It is not flat out bad, more like good enough for the application. My gripe here was more about Toyota claim regarding WS been a "lifetime fluid" that does not require replacement (Which I call a BS). I definitely would NOT put the drained stuff back in transmission and leave it there for another 5 years.

Going for OEM fluids is a way to go for most of the people as long as using incorrect (incompatible) fluid will eventually lead to catastrophic failures of very expensive components. But what turned me off from Toyota WS was its conventional base. And comparing conventional vs synthetic was no brainier for me. Synthetics will always have higher thermal stability and wear resistance. Amsoil just happened to be one of the compatible synthetic fluids. I would say with more realistic maintenance intervals ANY OEM or compatible fluid will do the job really good. I did Amsoil in both differentials and power steering system, did Prestone Dot 3 (Walmart stuff) brake fluid and only used Toyotas fluids for AHC system and transfer case because there are really no compatible analogs. So far transmission shifts noticeable better and smoother, although I thought 50k mileage was too low to see any changes in transmission behavior.

The same way I don't run Toyota engine oil for 10k miles and used Motul 0W20 for my last oil change, that I will drain after 5k miles and then even switch to Pennzoil Ultra Platinum Full Synthetic 5W30 (for 5K intervals in the future. Because I don't understand why the same engine (or similar ones) in different regions (UAE) and previous years are totally fine with 5W30 and in 2021 in US call for 0W20.

@RangerPepe-Great write up. I’m looking at doing the same services to my wife’s 2016 570 this Summer as well. Couple of questions
1-I checked the power steering fluid this weekend and it seems like the stuff in there is clearish, not red like I am use to in all of my other Toyota products. Any thoughts on this? Did you see the same fluid in yours prior to servicing?

2-I use the Amsoil Easy Paks for diff and T case fluid exchanges, Do you think these would work for the tranny fluid exchange? I just purchased the car and have not been underneath extensively yet.

3- Also, what fluid did you use in the T case? I have been told to use Toyota fluid only...
thanks in advance.

 

[TLC2013]

@RangerPepe-Great write up. I’m looking at doing the same services to my wife’s 2016 570 this Summer as well. Couple of questions
1-I checked the power steering fluid this weekend and it seems like the stuff in there is clearish, not red like I am use to in all of my other Toyota products. Any thoughts on this? Did you see the same fluid in yours prior to servicing?

2-I use the Amsoil Easy Paks for diff and T case fluid exchanges, Do you think these would work for the tranny fluid exchange? I just purchased the car and have not been underneath extensively yet.

3- Also, what fluid did you use in the T case? I have been told to use Toyota fluid only...
thanks in advance.

I used redline (ATF) for the power steering fluid. It’s a red cherry color. Not sure what’s in yours if its clearish in color. I changed mine after I bought my LC, fluid was reddish brown and may have been the original fluid at 80,000 miles.

I purchased Amsoil ATF in their gallon jugs (Cheaper by the bulk) for the tranny . Then will use a funnel and tubing to Refil.

For the transfer case I have been using Ravenol 75w. It’s around $15 a bottle on amazon. Has been getting good reviews with the tundra transfer case that also call for a 75w oil.

 

[Hokie99]

I used redline (ATF) for the power steering fluid. It’s a red cherry color. Not sure what’s in yours if its clearish in color. I changed mine after I bought my LC, fluid was reddish brown and may have been the original fluid at 80,000 miles.

I purchased Amsoil ATF in their gallon jugs (Cheaper by the bulk) for the tranny . Then will use a funnel and tubing to Refil.

For the transfer case I have been using Ravenol 75w. It’s around $15 a bottle on amazon. Has been getting good reviews with the tundra transfer case that also call for a 75w oil.

Thank you.

 

[RangerPepe]

@Hokie99
1. Power steering fluid can be discolored when it is getting old. Original stuff I drained was indeed clear-brownish color. I used AmsOil OE Multi-Vehicle Synthetic ATF as a replacement.
To replace the whole amount more or less here is the procedure I followed.

1. Drain PS fluid tank with transfer pump.​

2. Disconnect PS return line (top hose connected to PS fluid tank) and plug it with something (I used 5/8" ID clear PVC tubing from Home Depot sealed on one end).​

3. Put disconnected end of return line into some container to catch old fluid.​

4. Fill PS reservoir with fresh ATF around 4 oz.​

5. Jack the front of the car to take the front wheels of the ground (Set AHC to OFF)​

6. With engine OFF turn steering wheel all the way to the left. (That will drain old PS fluid out of return line and suck the fresh fluid in from the PS tank)​

7. Top off PS tank with new fluid.​

8. Turn steering wheel all the way to the right​

9. Top off PS tank.​

10. Do 6, 7, 8, 9 untill you have around 2oz of fresh ATF left and PS fluid tank is below return line level.​

11. Return the car back on the ground.​

11. Reconnect return line and top of PS tank to be between min and max of the COLD level marks.​

2. AmsOil easy-pack was handy for rear differential and probably would be candy for TC. Front differential and transmission fill plugs are located in the hard to reach areas. You will need to have a funnel with long tubing or just run PVC tubing to fill them. (Get a nice hand pump for transmission though. For me cheap transfer pump was taking to much time to fill it.)

3. For the transfer case I decided to suck it up and bought Toyota LF 75W (08885-81080) from the dealer $64 per litter and you gonna need 1.5 liters. People reporting that Ravenol fluid is good enough and that dealers also do not use Toyota LF. When I drain my TC fluid I was really surprised, out of all the fluids I did in the car I would say this one was done prematurely. Old fluid looked, smelled and felt like new and IMHO could have been fine for another 25k miles (Did my at 53k miles).

​

 

[Hokie99]

@Hokie99
1. Power steering fluid can be discolored when it is getting old. Original stuff I drained was indeed clear-brownish color. I used AmsOil OE Multi-Vehicle Synthetic ATF as a replacement.
To replace the whole amount more or less here is the procedure I followed.

1. Drain PS fluid tank with transfer pump.​

2. Disconnect PS return line (top hose connected to PS fluid tank) and plug it with something (I used 5/8" ID clear PVC tubing from Home Depot sealed on one end).​

3. Put disconnected end of return line into some container to catch old fluid.​

4. Fill PS reservoir with fresh ATF around 4 oz.​

5. Jack the front of the car to take the front wheels of the ground (Set AHC to OFF)​

6. With engine OFF turn steering wheel all the way to the left. (That will drain old PS fluid out of return line and suck the fresh fluid in from the PS tank)​

7. Top off PS tank with new fluid.​

8. Turn steering wheel all the way to the right​

9. Top off PS tank.​

10. Do 6, 7, 8, 9 untill you have around 2oz of fresh ATF left and PS fluid tank is below return line level.​

11. Return the car back on the ground.​

11. Reconnect return line and top of PS tank to be between min and max of the COLD level marks.​

2. AmsOil easy-pack was handy for rear differential and probably would be candy for TC. Front differential and transmission fill plugs are located in the hard to reach areas. You will need to have a funnel with long tubing or just run PVC tubing to fill them. (Get a nice hand pump for transmission though. For me cheap transfer pump was taking to much time to fill it.)

3. For the transfer case I decided to suck it up and bought Toyota LF 75W (08885-81080) from the dealer $64 per litter and you gonna need 1.5 liters. People reporting that Ravenol fluid is good enough and that dealers also do not use Toyota LF. When I drain my TC fluid I was really surprised, out of all the fluids I did in the car I would say this one was done prematurely. Old fluid looked, smelled and felt like new and IMHO could have been fine for another 25k miles (Did my at 53k miles).

​

That helps me tremendously, thank you.

 

[Hokie99]

@TLC2013 No problem, I just wanted to add something to the community, as I did find a lot of useful info here while bringing my car up to maintenance baseline. Let me know if you face some specifics that I missed in my write up.

@04UZJ100 I might have made a bold statement regarding WS fluid. It is not flat out bad, more like good enough for the application. My gripe here was more about Toyota claim regarding WS been a "lifetime fluid" that does not require replacement (Which I call a BS). I definitely would NOT put the drained stuff back in transmission and leave it there for another 5 years.

Going for OEM fluids is a way to go for most of the people as long as using incorrect (incompatible) fluid will eventually lead to catastrophic failures of very expensive components. But what turned me off from Toyota WS was its conventional base. And comparing conventional vs synthetic was no brainier for me. Synthetics will always have higher thermal stability and wear resistance. Amsoil just happened to be one of the compatible synthetic fluids. I would say with more realistic maintenance intervals ANY OEM or compatible fluid will do the job really good. I did Amsoil in both differentials and power steering system, did Prestone Dot 3 (Walmart stuff) brake fluid and only used Toyotas fluids for AHC system and transfer case because there are really no compatible analogs. So far transmission shifts noticeable better and smoother, although I thought 50k mileage was too low to see any changes in transmission behavior.

The same way I don't run Toyota engine oil for 10k miles and used Motul 0W20 for my last oil change, that I will drain after 5k miles and then even switch to Pennzoil Ultra Platinum Full Synthetic 5W30 (for 5K intervals in the future. Because I don't understand why the same engine (or similar ones) in different regions (UAE) and previous years are totally fine with 5W30 and in 2021 in US call for 0W20.

How’s the transmission shifting with that Amsoil, still noticeably better than the WS? I’m getting ready to do my wife’s 570 and would like to stick with Amsoil as that’s what I keep in bulk for all of my vehicles.

 

[RangerPepe]

How’s the transmission shifting with that Amsoil, still noticeably better than the WS? I’m getting ready to do my wife’s 570 and would like to stick with Amsoil as that’s what I keep in bulk for all of my vehicles.

Actually, it is still very good. Although I didn’t drive much since I replaced it (just around 1k miles), it still feels smooth and I am overall happy with the results. Will do drain and feel after 30k and post an update.

 

[Hokie99]

Actually, it is still very good. Although I didn’t drive much since I replaced it (just around 1k miles), it still feels smooth and I am overall happy with the results. Will do drain and feel after 30k and post an update.

Thank you fir the follow up!

 

[AnyMal]

Hi Ranger,

thanks for making this post.

Im getting ready to do a full ATF flush like this and from living under the truck last week was wondering if im blind for not seeing the thermostat valve.
Glad I'm doing more homework since i also had the wrong o ring for our fill plug. You just saved me a wasted morning.

At 62k, do you recommend dropping the pan for sure?
I will do so at 100-120 anyway but if your magnets were fully covered it has me rethinking my plans.

Also im a novice, and i dont fully understand your diagram. Should i be disconnecting the top hose only?
If thats the case how did you avoid sucking up air through that?
Shouldn't that have negative pressure from the feed line going back into the transmission wanting to draw in more fluid?

My plan for this is to funnel tube / grav feed fresh fluid into the fill port while starting and stopping the engine just like you described and shifting through the range.
I have 12qts of WS and will be very careful on the last cycle and will remove/add only 2 at each interval straight from the containers.
My catch bucket is graduated as well and will be monitored like a hawk.

I will be using Techstream to monitor the temp for the overflow leveling but since we are missing the forced open thermostat valve, is that enough for us to ensure the system is fully cycling ALL of the fluid and im not just measuring whats in the pan?
I know with the OBDII procedure the vehicle is in fluid leveling mode so im thinking that just reading out the temp is not enough on our year / model.

Is there any other precaution i need to take other than the two questions above and not letting it get air inside? Can you run a trans "dry" and damage it?

Sorry about all of the questions but the official procedure is nowhere near good enough and would require 9x swap to get only 95% of the fluid replaced per someones math here on the subject. I want to be sure that i dont miss the vehicles correct diagnostic mode when doing this hybrid procedure.

@bloc because bugging you is my new hobby and i realized Ranger hasn't logged in in almost two months.
Also calling all resident gearheads. You are all an asset and wealth of information so thanks in advance.

 

[bloc]

The feed to the coolers is essentially a bleed from the ATF pump and the whole purpose is to cycle the full volume of the transmission through the coolers periodically. On this flow circuit nothing else is done with the fluid. It simply dumps back into the pan, where any air will separate before the fluid is drawn into the pump again.

The return line to the trans from the coolers doesn’t have suction, it depends on the positive pressure being fed into the coolers for that fluid to be pushed back to the pan. I usually plug the return line but that is more about avoiding it dripping and making a mess than it is being worried air will get back to the transmission.

I can’t speak to the lack of a thermostat.. haven’t had a chance to stare at an 8spd yet.

 

[AnyMal]

In that case shouldn't the appropriate drain point be the coolers outlet not the trans pump line as to flush that as well and not leave any old fluid inside?

 

[bloc]

In that case shouldn't the appropriate drain point be the coolers outlet not the trans pump line as to flush that as well and not leave any old fluid inside?

In the grand scheme it is a small percentage.

It’s been a while since I did mine but I think I grabbed the line before it returned.

 

[RangerPepe]

Lads, I am still following this forum as it proved to be a valuable source if information.

[B]@NeMal51[/B], I would say dropping a pan was unnecessary for my case at 52K miles yes there was some dust and a bit of sludge build up on the magnets but IMHO they would have been just fine with double that amount easily. Also, from my research I have come to the conclusion that under normal scenario of fluid change you don’t need to worry about our ATF filter at least 120k-150k miles. (If you just changing fluid not doing a clutch pack replacement or anything crazy, I would leave it alone)

From what I did and as [B]@bloc[/B] already mentioned. You need to disconnect just the top hose, don’t worry about suction or anything. There is no vacuum at the return side. The fluid is pushed by the pump thru the main and auxiliary coolers, and picked up from the drain pan thru the ATF oil filter/oil strainer. Although I didn’t see it myself, I am pretty sure ATF fluid drops from the cooler line inlet right to the oil pan. Besides, transmission pan+case is not a completely sealed system it has some air inside and even have a breather tube.

You got right the idea NOT to run the transmission dry, I did 3 qts at a time to be careful, If you will do 2 quarts at a time you will be just fine. I’d only suggest you put 1 extra quart of ATF fluid in the transmission in the fill port before you start drain/fill procedure just to stay on the safe side.

While doing ATF leveling procedure, I had a feeling it was not just about the temperature. When the procedure “kicked in” I think engine got in a particular RPM range as well. However, if you are using techstream, you should be good to go. If you want to be extra careful you can get a proper write up for the procedure at techinfo.toyota.com for ATF fluid level check/adjustment. Man… these 20 bucks saved me a ton of headache and not just for ATF, all the torque spec and everything else is there in the repair manual.

Yes, overall, you CAN damage transmission if you run it dry. Just add extra quart before and do 2 qt at a time you will be fine. Don’t worry about “air suction” this is not the case here. Good luck. I was able to do it right all by myself for the first time, so do you.

BTW as an update after 4.000 mile on AmsOIL ATF, Truck still runs and shifts very smooth as on the day I swapped original fluid. Our famous 1st to 2nd gear kick still exists but I almost don’t feel it anymore.

 

[AnyMal]

Lads, I am still following this forum as it proved to be a valuable source if information.

[B]@NeMal51[/B], I would say dropping a pan was unnecessary for my case at 52K miles yes there was some dust and a bit of sludge build up on the magnets but IMHO they would have been just fine with double that amount easily. Also, from my research I have come to the conclusion that under normal scenario of fluid change you don’t need to worry about our ATF filter at least 120k-150k miles. (If you just changing fluid not doing a clutch pack replacement or anything crazy, I would leave it alone)

From what I did and as [B]@bloc[/B] already mentioned. You need to disconnect just the top hose, don’t worry about suction or anything. There is no vacuum at the return side. The fluid is pushed by the pump thru the main and auxiliary coolers, and picked up from the drain pan thru the ATF oil filter/oil strainer. Although I didn’t see it myself, I am pretty sure ATF fluid drops from the cooler line inlet right to the oil pan. Besides, transmission pan+case is not a completely sealed system it has some air inside and even have a breather tube.

You got right the idea NOT to run the transmission dry, I did 3 qts at a time to be careful, If you will do 2 quarts at a time you will be just fine. I’d only suggest you put 1 extra quart of ATF fluid in the transmission in the fill port before you start drain/fill procedure just to stay on the safe side.

While doing ATF leveling procedure, I had a feeling it was not just about the temperature. When the procedure “kicked in” I think engine got in a particular RPM range as well. However, if you are using techstream, you should be good to go. If you want to be extra careful you can get a proper write up for the procedure at techinfo.toyota.com for ATF fluid level check/adjustment. Man… these 20 bucks saved me a ton of headache and not just for ATF, all the torque spec and everything else is there in the repair manual.

Yes, overall, you CAN damage transmission if you run it dry. Just add extra quart before and do 2 qt at a time you will be fine. Don’t worry about “air suction” this is not the case here. Good luck. I was able to do it right all by myself for the first time, so do you.

BTW as an update after 4.000 mile on AmsOIL ATF, Truck still runs and shifts very smooth as on the day I swapped original fluid. Our famous 1st to 2nd gear kick still exists but I almost don’t feel it anymore.

I do have all of the resources to read through and appreciate the input!

From the service manual that seems to be the only valid way to do a proper fill level with our electronic thermostat valve.
The procedure is a bit complex for operating temp fluid level and that is very interesting that you report the RPM fluctuates.
Ive got TS and will be adjusting my plan according to this and start off with excess fluid.


Also, while im not so sure its the same as the 2016 jerk TSB I do have a slight bump during 1-2 shift.
Ive got the 17 as well and have been wondering if a flush would help. My vehicle does not have the TSB update sticker for the transmission computer.
Have you heard of this? Maybe that can solve it or perhaps our slight bump is indeed the "solved" issue.
Or perhaps the transmission fill procedure is part of the problem?

If anyone reading has had that update done please let me know your experience before/after.
I don't want to get rid of the bump and gain some other odd behavior instead.

Full bulletin attached.

 

[04UZJ100]

The feed to the coolers is essentially a bleed from the ATF pump and the whole purpose is to cycle the full volume of the transmission through the coolers periodically. On this flow circuit nothing else is done with the fluid. It simply dumps back into the pan, where any air will separate before the fluid is drawn into the pump again.

The return line to the trans from the coolers doesn’t have suction, it depends on the positive pressure being fed into the coolers for that fluid to be pushed back to the pan. I usually plug the return line but that is more about avoiding it dripping and making a mess than it is being worried air will get back to the transmission.

I can’t speak to the lack of a thermostat.. haven’t had a chance to stare at an 8spd yet.

No thermostats on my 2020.

 

[RangerPepe]

I do have all of the resources to read through and appreciate the input!

From the service manual that seems to be the only valid way to do a proper fill level with our electronic thermostat valve.
The procedure is a bit complex for operating temp fluid level and that is very interesting that you report the RPM fluctuates.
Ive got TS and will be adjusting my plan according to this and start off with excess fluid.


Also, while im not so sure its the same as the 2016 jerk TSB I do have a slight bump during 1-2 shift.
Ive got the 17 as well and have been wondering if a flush would help. My vehicle does not have the TSB update sticker for the transmission computer.
Have you heard of this? Maybe that can solve it or perhaps our slight bump is indeed the "solved" issue.
Or perhaps the transmission fill procedure is part of the problem?

If anyone reading has had that update done please let me know your experience before/after.
I don't want to get rid of the bump and gain some other odd behavior instead.

View attachment 2819400

Full bulletin attached.

Hey, thanks for the TSB I didn't know about this one. I don't think the problem with the jerk related to the AT fill in anyway was there from the day 1. I think all 8-speeds on LC and LX are affected by this. The symptom is when you are rolling down to the red light or stop sign reducing your speed below 10 MPH and then proceed with acceleration the car has a pronounced jerk while engaging 2nd gear. I know there was a LC TSB for that and people sad it worked for them. But I was not able to persuade my dealer to apply this one to LX. That damn ain't broke it - don't touch it mentality. These LCs and LXs are so rare that the vast majority of techs lack required knowledge and experience to work on them. (If you want to diagnose Lexus AHC or something like this ... forget it. This forum will be your best bet.)