Rx #00 Transmission Problem?

[miller5]

I am kind of new to this forum (one other post last year) and am not quite sure how to post these things so bear with me

My wife has a 200 RX 300 and a few months ago it wouldn't go into reverse either. It did it a few times with her and then stopped. I went and had the transmission flushed (not at a dealer) with the assurance and promise from the service tech that I wouldn't have any transmission problems because of the flush. This was done Back in May.

A few days ago I noticed that it would shift hard between 1st and 2nd gear before the engine got warmed up. After the engine warms up it shifts fine. Then yesterday it slipped slightly (again when cold). The check engine light also came on for @ 5 minutes then it went off (wasn't flashing). I have a mechanic friend who works at the Toyota dealership as a technician and he said that the flush probably is the culprit and the tranmission is probably going bad because of the flush.

The car has 130k on it and has never given us any problems until now. Could it be:

-the knock sensor

-speed sensors

-that they didin't put the type IV fluid in it that is required? I called them to see if they put it in Lexus' when they flush them and the man said "they can.....but they need a heads up before the work is done so they can get the fluid in"......

HELP...... :(

[PK_3]

If it's any consolation, my trans went at 65k.. I was told at the time it was not unusual.

Good Luck

[smooth1]

I am kind of new to this forum (one other post last year) and am not quite sure how to post these things so bear with me

My wife has a 200 RX 300 and a few months ago it wouldn't go into reverse either. It did it a few times with her and then stopped. I went and had the transmission flushed (not at a dealer) with the assurance and promise from the service tech that I wouldn't have any transmission problems because of the flush. This was done Back in May.

A few days ago I noticed that it would shift hard between 1st and 2nd gear before the engine got warmed up. After the engine warms up it shifts fine. Then yesterday it slipped slightly (again when cold). The check engine light also came on for @ 5 minutes then it went off (wasn't flashing). I have a mechanic friend who works at the Toyota dealership as a technician and he said that the flush probably is the culprit and the tranmission is probably going bad because of the flush.

The car has 130k on it and has never given us any problems until now. Could it be:

-the knock sensor

-speed sensors

-that they didin't put the type IV fluid in it that is required? I called them to see if they put it in Lexus' when they flush them and the man said "they can.....but they need a heads up before the work is done so they can get the fluid in"......

HELP...... :(

Unfortunately, your friend at the dealership could be correct. HAve you had the transmission flushed regularly before? I see this problem alot. Flushing your trans always sounds like a great idea, but only if you have done it form the beginning and thru out the life of the trans. The issue is the heat from the trans breaks down the fluid, which reacts with the surfaces of all the internal components causing them to tarnish and create sludge. Once this has happened it is better to leave it alone, and just replace the fluid 3-4 quarts at a time from the pan. Because if you remove all the tranish and sludge, what you leave behind are gaps and spaces that cause the transmission to slip and stick. If this starts to happen, the only thing you can do is drive it while you save up for a transmission rebuild or a new transmission.

that they didin't put the type IV fluid in it that is required? I called them to see if they put it in Lexus' when they flush them and the man said "they can.....but they need a heads up before the work is done so they can get the fluid in"......

This is ridiculuos! It's up to them to know what the correct fluid is. Alot of car manufacturers have very specific ATF requirements. If they are unaware of them, then they are not qualified to be performing transmission flushes! He was giving you the " I'm an idiot, heres some BS, now go away." line! If they didn't replace the fluid with the correct one, then you very could have a case for the issues your having.

[miller5]

I am kind of new to this forum (one other post last year) and am not quite sure how to post these things so bear with me

My wife has a 200 RX 300 and a few months ago it wouldn't go into reverse either. It did it a few times with her and then stopped. I went and had the transmission flushed (not at a dealer) with the assurance and promise from the service tech that I wouldn't have any transmission problems because of the flush. This was done Back in May.

A few days ago I noticed that it would shift hard between 1st and 2nd gear before the engine got warmed up. After the engine warms up it shifts fine. Then yesterday it slipped slightly (again when cold). The check engine light also came on for @ 5 minutes then it went off (wasn't flashing). I have a mechanic friend who works at the Toyota dealership as a technician and he said that the flush probably is the culprit and the tranmission is probably going bad because of the flush.

The car has 130k on it and has never given us any problems until now. Could it be:

-the knock sensor

-speed sensors

-that they didin't put the type IV fluid in it that is required? I called them to see if they put it in Lexus' when they flush them and the man said "they can.....but they need a heads up before the work is done so they can get the fluid in"......

HELP...... :(

Unfortunately, your friend at the dealership could be correct. HAve you had the transmission flushed regularly before? I see this problem alot. Flushing your trans always sounds like a great idea, but only if you have done it form the beginning and thru out the life of the trans. The issue is the heat from the trans breaks down the fluid, which reacts with the surfaces of all the internal components causing them to tarnish and create sludge. Once this has happened it is better to leave it alone, and just replace the fluid 3-4 quarts at a time from the pan. Because if you remove all the tranish and sludge, what you leave behind are gaps and spaces that cause the transmission to slip and stick. If this starts to happen, the only thing you can do is drive it while you save up for a transmission rebuild or a new transmission.

that they didin't put the type IV fluid in it that is required? I called them to see if they put it in Lexus' when they flush them and the man said "they can.....but they need a heads up before the work is done so they can get the fluid in"......

This is ridiculuos! It's up to them to know what the correct fluid is. Alot of car manufacturers have very specific ATF requirements. If they are unaware of them, then they are not qualified to be performing transmission flushes! He was giving you the " I'm an idiot, heres some BS, now go away." line! If they didn't replace the fluid with the correct one, then you very could have a case for the issues your having.

According to them it wouldn't have taken this long for the problem to show up if it was a flush problem. I have read other posts here that mimick my problem and the advise was to clean the speed sensors and put them back on or possibly the knock sensor....any thoughts? :(

[miller5]

I am kind of new to this forum (one other post last year) and am not quite sure how to post these things so bear with me

My wife has a 200 RX 300 and a few months ago it wouldn't go into reverse either. It did it a few times with her and then stopped. I went and had the transmission flushed (not at a dealer) with the assurance and promise from the service tech that I wouldn't have any transmission problems because of the flush. This was done Back in May.

A few days ago I noticed that it would shift hard between 1st and 2nd gear before the engine got warmed up. After the engine warms up it shifts fine. Then yesterday it slipped slightly (again when cold). The check engine light also came on for @ 5 minutes then it went off (wasn't flashing). I have a mechanic friend who works at the Toyota dealership as a technician and he said that the flush probably is the culprit and the tranmission is probably going bad because of the flush.

The car has 130k on it and has never given us any problems until now. Could it be:

-the knock sensor

-speed sensors

-that they didin't put the type IV fluid in it that is required? I called them to see if they put it in Lexus' when they flush them and the man said "they can.....but they need a heads up before the work is done so they can get the fluid in"......

HELP...... :(

Unfortunately, your friend at the dealership could be correct. HAve you had the transmission flushed regularly before? I see this problem alot. Flushing your trans always sounds like a great idea, but only if you have done it form the beginning and thru out the life of the trans. The issue is the heat from the trans breaks down the fluid, which reacts with the surfaces of all the internal components causing them to tarnish and create sludge. Once this has happened it is better to leave it alone, and just replace the fluid 3-4 quarts at a time from the pan. Because if you remove all the tranish and sludge, what you leave behind are gaps and spaces that cause the transmission to slip and stick. If this starts to happen, the only thing you can do is drive it while you save up for a transmission rebuild or a new transmission.

that they didin't put the type IV fluid in it that is required? I called them to see if they put it in Lexus' when they flush them and the man said "they can.....but they need a heads up before the work is done so they can get the fluid in"......

This is ridiculuos! It's up to them to know what the correct fluid is. Alot of car manufacturers have very specific ATF requirements. If they are unaware of them, then they are not qualified to be performing transmission flushes! He was giving you the " I'm an idiot, heres some BS, now go away." line! If they didn't replace the fluid with the correct one, then you very could have a case for the issues your having.

According to them it wouldn't have taken this long for the problem to show up if it was a flush problem. I have read other posts here that mimick my problem and the advise was to clean the speed sensors and put them back on or possibly the knock sensor....any thoughts? :(

We are the 2nd owners of this car and the only time the transmission was done was a drop and fill.....

[smooth1]

Without me being able to look at you car directly, the cel could even be unrelated at this point. An 02 senser wouldn't have anything to do with the slipping of the tranny or the hard shift. Those are signs of more problems to come. I would atleasat change the tranny fluid to the correct type 4 asap.

And I haven't noticed any set amount of time for these issues to start happening. Sometimes it doesn't even become an issue. I've seen people flush for the first time at 100k miles and not seem to have any problems, and I've seen some flush at the same time and have tons of trouble afterwards, sometimes right away, but mostly I have seen the problems start about a month afterwards. I guess it could depend on how much they drive the car. It's a crap shoot at that point. Sometimes it's where the tarnish is and how the sludge inside is built up, and just how much. There is a speed sensor on the transmission as well. That could be related. The MAF feeds info for the shift points also, so it could be that. I would suggest going in for a full diagnostic and find out for sure. If the cel came on breifly, then an event has been logged in the ECU and can be retrieved. A good tech will see that on the scan and be able to investigate it.

[miller5]

Without me being able to look at you car directly, the cel could even be unrelated at this point. An 02 senser wouldn't have anything to do with the slipping of the tranny or the hard shift. Those are signs of more problems to come. I would atleasat change the tranny fluid to the correct type 4 asap.

And I haven't noticed any set amount of time for these issues to start happening. Sometimes it doesn't even become an issue. I've seen people flush for the first time at 100k miles and not seem to have any problems, and I've seen some flush at the same time and have tons of trouble afterwards, sometimes right away, but mostly I have seen the problems start about a month afterwards. I guess it could depend on how much they drive the car. It's a crap shoot at that point. Sometimes it's where the tarnish is and how the sludge inside is built up, and just how much. There is a speed sensor on the transmission as well. That could be related. The MAF feeds info for the shift points also, so it could be that. I would suggest going in for a full diagnostic and find out for sure. If the cel came on breifly, then an event has been logged in the ECU and can be retrieved. A good tech will see that on the scan and be able to investigate it.

Thanks for your advise. I appreciate your input. Where is the speed sensor located? Is there anywhere on this site that shows you where they are located. According to a few posts that I've read, they are easy to get to and clean...

[smooth1]

I'm not exactly sure on the RX. But if you get under the car and look at the trans, you can easily find it with your hand, or see it clear as day. they are the only things sticking out of you trans with a wire connected to it like a spark plug. It just screws out.

[miller5]

I'm not exactly sure on the RX. But if you get under the car and look at the trans, you can easily find it with your hand, or see it clear as day. they are the only things sticking out of you trans with a wire connected to it like a spark plug. It just screws out.

Before I take them out should I remove the neg battery cable or does it matter?

[smooth1]

That is a trick question in your case. But a good to one to raise. If you disconnect the battery, you'll effectively reset the ECU also. SO the events that have happened will be cleared and if cleaning the sensors ends up not fixing anything, then when you take it in, they won't be able to look at the performance history and look at the events logged in the ECU, hence you'll waste that time and money again. BUt in order to clean the sensors, it is a good idea to disconnect the battery and reset the ECU.

Which is why I think you might want to consider just taking it in and atleast doing the diagnostic to get the right problem fixed.(I'm not talking about the Auto Zone scan they do for free, they only read you the cel code.) I see alot of people buy parts and end up spending as much money if not more doing that then just getting the diagnostic and fixing the correct problem. I in no way am saying that the diagnostic is a 100% tool, but it could end up saving you time, money and hassles. If your RX and other cars are starting to approach higher mileage and you intend on keeping them , I suggest to all my friends that they invest in an ODB II scanner that has freeze frame and enhanced detail code readings as if you have to have you car diagnosed even 2 or 3 times, it has just payed for itself. And even if it does show something that you are unable to fix, it is allways better to go a mechanic armed with knowledge then be at thier diagnostic mercy.

[mikey00]

First off, don't get under the car to look for sensors, as advised. They are on the top of the trans and not visible from underneath the car. One is directly underneath the air box and you need to remove the air box to see it. Removing the air box is not that hard. The other sits at about a 45 degree angle facing the battery and can be seen without removing anything.

A flush sometimes moves some small metallic dust around in the trans and it ends up clinging to these magnetic sensors causing them to malfunction. I would pull both of them, clean them and swap their positions without disconnecting the battery cable. This will most likely fix your reverse issue and stands a chance of fixing other issues as well. If it doesn't fix anything you now have to make the decision of getting the codes read or just disconnecting the battery and resetting everything. My personal preference would be to just reset everything and give it a try. If the problem is still there the code will return, so nothing lost. If the problem is fixed, who cares what the code was.

As far as the trans fluid goes, it sounds to me like the shop used a compatible fluid and if you wanted genuine Lexus (Toyota Type T-IV) they would need a heads up. Sounds fair enough. You may want to verify this with them. Given the known trans problems with the RX many, myself included, prefer to use nothing but Toyota Type T-IV. Others have used a compatible fluid without any problems. As long as that's what they did you should be fine.

Here is a pic of the sensors on a trans and I have basic removal directions in the post below the pic.

http://www.clublexus.com/forums/showthread...t=speed+sensors

[miller5]

First off, don't get under the car to look for sensors, as advised. They are on the top of the trans and not visible from underneath the car. One is directly underneath the air box and you need to remove the air box to see it. Removing the air box is not that hard. The other sits at about a 45 degree angle facing the battery and can be seen without removing anything.

A flush sometimes moves some small metallic dust around in the trans and it ends up clinging to these magnetic sensors causing them to malfunction. I would pull both of them, clean them and swap their positions without disconnecting the battery cable. This will most likely fix your reverse issue and stands a chance of fixing other issues as well. If it doesn't fix anything you now have to make the decision of getting the codes read or just disconnecting the battery and resetting everything. My personal preference would be to just reset everything and give it a try. If the problem is still there the code will return, so nothing lost. If the problem is fixed, who cares what the code was.

As far as the trans fluid goes, it sounds to me like the shop used a compatible fluid and if you wanted genuine Lexus (Toyota Type T-IV) they would need a heads up. Sounds fair enough. You may want to verify this with them. Given the known trans problems with the RX many, myself included, prefer to use nothing but Toyota Type T-IV. Others have used a compatible fluid without any problems. As long as that's what they did you should be fine.

Here is a pic of the sensors on a trans and I have basic removal directions in the post below the pic.

http://www.clublexus.com/forums/showthread...t=speed+sensors

Ok thanks for the information...you guys have been great and possibly a lifesaver.....I'll let you know what happens.... ;)

[miller5]

That is a trick question in your case. But a good to one to raise. If you disconnect the battery, you'll effectively reset the ECU also. SO the events that have happened will be cleared and if cleaning the sensors ends up not fixing anything, then when you take it in, they won't be able to look at the performance history and look at the events logged in the ECU, hence you'll waste that time and money again. BUt in order to clean the sensors, it is a good idea to disconnect the battery and reset the ECU.

Which is why I think you might want to consider just taking it in and atleast doing the diagnostic to get the right problem fixed.(I'm not talking about the Auto Zone scan they do for free, they only read you the cel code.) I see alot of people buy parts and end up spending as much money if not more doing that then just getting the diagnostic and fixing the correct problem. I in no way am saying that the diagnostic is a 100% tool, but it could end up saving you time, money and hassles. If your RX and other cars are starting to approach higher mileage and you intend on keeping them , I suggest to all my friends that they invest in an ODB II scanner that has freeze frame and enhanced detail code readings as if you have to have you car diagnosed even 2 or 3 times, it has just payed for itself. And even if it does show something that you are unable to fix, it is allways better to go a mechanic armed with knowledge then be at thier diagnostic mercy.

Good point about the scanner. What does one run @ $125...?

[smooth1]

You can start there. That is probably a good ballpark number. I would just make sure the one you get has freeze frame and enhanced code readings. Then you can read your own codes, clear them, and do your own freeze frame of the event as it happens so you don't need to duplicate the problem over and over again in order to chase it down.

[miller5]

That is a trick question in your case. But a good to one to raise. If you disconnect the battery, you'll effectively reset the ECU also. SO the events that have happened will be cleared and if cleaning the sensors ends up not fixing anything, then when you take it in, they won't be able to look at the performance history and look at the events logged in the ECU, hence you'll waste that time and money again. BUt in order to clean the sensors, it is a good idea to disconnect the battery and reset the ECU.

Which is why I think you might want to consider just taking it in and atleast doing the diagnostic to get the right problem fixed.(I'm not talking about the Auto Zone scan they do for free, they only read you the cel code.) I see alot of people buy parts and end up spending as much money if not more doing that then just getting the diagnostic and fixing the correct problem. I in no way am saying that the diagnostic is a 100% tool, but it could end up saving you time, money and hassles. If your RX and other cars are starting to approach higher mileage and you intend on keeping them , I suggest to all my friends that they invest in an ODB II scanner that has freeze frame and enhanced detail code readings as if you have to have you car diagnosed even 2 or 3 times, it has just payed for itself. And even if it does show something that you are unable to fix, it is allways better to go a mechanic armed with knowledge then be at thier diagnostic mercy.

Update: Cleaned the MAF sensor and cleaned and switched the speed sensors. The first speed sensor that I took out (the one that is 45 degrees from the battery) had some sludge on it but the other one had the pink transmission fluid on it.

Drives great so far-better than when we bought it a couple of years ago. I will keep you posted. If this doesn't fix the problem when will I know? Should I go ahead and get the transmission fluid replaced just to be sure it has the right kind in it? Because the first sensor had sludge on it, does that mean they didn't flush it like they said they did?

[miller5]

First off, don't get under the car to look for sensors, as advised. They are on the top of the trans and not visible from underneath the car. One is directly underneath the air box and you need to remove the air box to see it. Removing the air box is not that hard. The other sits at about a 45 degree angle facing the battery and can be seen without removing anything.

A flush sometimes moves some small metallic dust around in the trans and it ends up clinging to these magnetic sensors causing them to malfunction. I would pull both of them, clean them and swap their positions without disconnecting the battery cable. This will most likely fix your reverse issue and stands a chance of fixing other issues as well. If it doesn't fix anything you now have to make the decision of getting the codes read or just disconnecting the battery and resetting everything. My personal preference would be to just reset everything and give it a try. If the problem is still there the code will return, so nothing lost. If the problem is fixed, who cares what the code was.

As far as the trans fluid goes, it sounds to me like the shop used a compatible fluid and if you wanted genuine Lexus (Toyota Type T-IV) they would need a heads up. Sounds fair enough. You may want to verify this with them. Given the known trans problems with the RX many, myself included, prefer to use nothing but Toyota Type T-IV. Others have used a compatible fluid without any problems. As long as that's what they did you should be fine.

Here is a pic of the sensors on a trans and I have basic removal directions in the post below the pic.

http://www.clublexus.com/forums/showthread...t=speed+sensors

Ok thanks for the information...you guys have been great and possibly a lifesaver.....I'll let you know what happens.... ;)

Cleaned the MAF sensor and cleaned and switched the speed sensors. The first speed sensor that I took out (the one that is 45 degrees from the battery) had some sludge on it but the other one had the pink transmission fluid on it.

Drives great so far-better than when we bought it a couple of years ago. I will keep you posted. If this doesn't fix the problem when will I know? Should I go ahead and get the transmission fluid replaced just to be sure it has the right kind in it? Because the first sensor had sludge on it, does that mean they didn't flush it like they said they did?

[mikey00]

It's impossible to tell if they did a flush or not. Being that you really have no reason to doubt them, they most likely did the flush as requested. A flush often moves dirt around in the trans and can deposit it on a sensor and cause problems (that's what happend to me). As long as they used a compatible fluid (even though it wasn't genuine Lexus/Toyota), I wouldn't worry about it. If you really wanted to go back to Lexus/Toyota fluid you would have to do another flush using Lexus/Toyota fluid. A drain and fill only removes about 1/2 of the fluid. As long as everything is working fine, I would let things be.

[miller5]

It's impossible to tell if they did a flush or not. Being that you really have no reason to doubt them, they most likely did the flush as requested. A flush often moves dirt around in the trans and can deposit it on a sensor and cause problems (that's what happend to me). As long as they used a compatible fluid (even though it wasn't genuine Lexus/Toyota), I wouldn't worry about it. If you really wanted to go back to Lexus/Toyota fluid you would have to do another flush using Lexus/Toyota fluid. A drain and fill only removes about 1/2 of the fluid. As long as everything is working fine, I would let things be.

Any thoughts on how long before I know if this problem is really fixed?

[smooth1]

I wouldn't say they didn't flush it, as I'm sure they did. I may have misunderstood you in that I thought you meant they put in the wrong fluid. Not just a different brand. But you might want to call them and find out exactly what they did use and find out for yourself if you should replace it again or not.

I'm glad to hear you may have fixed it. Hopefully that is the issue in it's intirety. I would still consider getting an ODB II scanner sometime in the near future though. All cars are run by sensors now, so being able to track down which one will help you alot in the future.

[mikey00]

It's impossible to tell if they did a flush or not. Being that you really have no reason to doubt them, they most likely did the flush as requested. A flush often moves dirt around in the trans and can deposit it on a sensor and cause problems (that's what happend to me). As long as they used a compatible fluid (even though it wasn't genuine Lexus/Toyota), I wouldn't worry about it. If you really wanted to go back to Lexus/Toyota fluid you would have to do another flush using Lexus/Toyota fluid. A drain and fill only removes about 1/2 of the fluid. As long as everything is working fine, I would let things be.

Any thoughts on how long before I know if this problem is really fixed?

That's a tough question. It all depends on the frequency of the problems you were having and how many cycles you go through problem free before feeling comfortable that it is fixed.

[miller5]

It's impossible to tell if they did a flush or not. Being that you really have no reason to doubt them, they most likely did the flush as requested. A flush often moves dirt around in the trans and can deposit it on a sensor and cause problems (that's what happend to me). As long as they used a compatible fluid (even though it wasn't genuine Lexus/Toyota), I wouldn't worry about it. If you really wanted to go back to Lexus/Toyota fluid you would have to do another flush using Lexus/Toyota fluid. A drain and fill only removes about 1/2 of the fluid. As long as everything is working fine, I would let things be.

Any thoughts on how long before I know if this problem is really fixed?

That's a tough question. It all depends on the frequency of the problems you were having and how many cycles you go through problem free before feeling comfortable that it is fixed.

Just got in it to goto lunch and when I put it in reverse it started bucking. Is the transmission shot or do I need to get new sensors?

[miller5]

I wouldn't say they didn't flush it, as I'm sure they did. I may have misunderstood you in that I thought you meant they put in the wrong fluid. Not just a different brand. But you might want to call them and find out exactly what they did use and find out for yourself if you should replace it again or not.

I'm glad to hear you may have fixed it. Hopefully that is the issue in it's intirety. I would still consider getting an ODB II scanner sometime in the near future though. All cars are run by sensors now, so being able to track down which one will help you alot in the future.

Got in it to go to lunch and when I put it in reverse it bucked a few times.....Should I buy new sensors, trans fluid before getting another transmission?

[smooth1]

I would check those snesors again first. Maybe pull em and see if they need cleaning again, then switch them back. Maybe consider doing this a few times to make sure it's not the problem before moving on. You may need to replace the sensors. It's hard to say with out the ODB II scan to tell us whats going on.

[miller5]

I would check those snesors again first. Maybe pull em and see if they need cleaning again, then switch them back. Maybe consider doing this a few times to make sure it's not the problem before moving on. You may need to replace the sensors. It's hard to say with out the ODB II scan to tell us whats going on.

ok thx...

[mikey00]

I would check those snesors again first. Maybe pull em and see if they need cleaning again, then switch them back. Maybe consider doing this a few times to make sure it's not the problem before moving on. You may need to replace the sensors. It's hard to say with out the ODB II scan to tell us whats going on.

ok thx...

I really don't think the scan tool is going to help here without getting a check engine light. The sensors in the RX act up and send out bad readings causing trans problems like the reverse issue. Problem is the ECM is not recognizimng sensor failure and does not generate a code. I know there are OBDII codes for the sensor, that you will get if the sensor flat out fails, but that is not the case.

I am sure you have the sensors clean, because I have done this before and there is not much to it. Just wipe it off. The big question here is: Does the RX react differently when the sensors are swapped?. You may want to swap again to verify this. I would expect you to have the reverse issue when they are in one position and some kind of foward shifting issue when they are in the other position. If this is the case one of the sensors must be bad. I would just replace them both. If you are going to do this you have to verify which ones you have. They are either Aisin Seiki or Toyota. The Aisin Seiki are labeled Aisin Seiki on one side of the sensor and Toyota on the other side. I am not sure how the Toyota ones are labeled, most likely Toyota on both sides. You can get them from rockauto.com for about $70/each. They are under cruise control sensors.

I don't really suspect the fluid unless they didn't use a compatible fluid. If that's the case you could do another flush to get all the fluid out and replace with Toyota type T-IV.

If it were me lastly I would drop the trans pan to make sure the trans filter isn't plugged. This shouldn't be the case as the factory filter is a free flowing screen. Unless someone changed it to a paper filter when they serviced the trans previously.