Quick question:

2001 LS, 158k miles. Transmission working well, I think

Some months ago (7k km ago) we did a drain and fill where the mechanic had overfilled the gearbox. To correct this, another mechanic at the same shop took a vacuum and drained about a liter and a bit out. It was then reading low so we added another 200-300ml and it was reading just below full.

The fluid that was taken out was very dark.

Before the drain and fill, the liquid was sort of amber in color so I knew a couple of drain and fills were in order. Because of this particular case, we ended up using about 4.5L of the 5L jug I had bought from Toyota (T-IV, yes) so I thought that the D+F at this stage had replaced quite a lot of fluid...maybe too much in one go?

Now, on the dipstick, the fluid is red, but more wine than red, with black suspended dust on it. My mechanic had suggested a filter replacement but, after reading a few posts here I am not sure this is an actively serviceable item. I have the OEM with me and wonder if I should do it or continue with another D+F until the fluid is cleaner and not drop the pan if not needed.

At the start I said that I think the transmission is working well. Reason I ask is because I tend to be a very gentle driver and where I live there are tons of 30kmh, 40kmh speed limits with plenty of speed bumps (the ones you need to go at 20kmh to not be jarred by them) so when I accelerate I tend to be gentle to go from 18-20 to 30/40 because 15 seconds later I will encounter another speed bump so I will have to brake again, repeat maybe a dozen times. So I noticed that going 1st to 2nd in this situations the car hesitates a bit or, I feel the change with a thud (not a strong one, but I can feel the change) In other situations it will downshift and the car would want to take off at this point: a strong pull. I can mitigate this behavior if:

1) I accelerate harder than I am accustomed to and the change happens at 1400-1600rpm
2) I switch the ECT to PWR which then stays in gear a bit more and makes the throttle more sensitive (less foot input distance for same power as a longer throttle pedal push)

So, I am wondering if the transmission is acting up as I often see it changing gears between 1000rpm-1200rpm with my driving.
Or, perhaps I am being too gentle on the throttle and I need to give more gas to it.

Other than this, the AT seems really smooth. I can barely feel the shifts when on roads at 40-90-120kmh.

Open to suggestions.

I have considered the MAF sensor as a potential source of this but since my fuel economy seems rather decent, and the OBD scanner is reading about 5g/s at idle once warm, I am unsure if it could be it.

 

Disconnect battery to reset the learning of the ecu. Hope the overfill did not damage the thansmission as it can.

 

Yep, this is why people say not to touch your transmission if it's not regularly serviced. I think there's an actual TCU reset procedure using a paperclip and shorting the leads on your obdII port in order to do a transmission relearn. Idk where it's at but use the Advanced search function and look for TCU reset. FYI when you refill you need to have the car engine on in Park. I guess for the 01-04's with the 5-speed you still have the dip stick so either way. But that may of been what happened the 1st time. Also the fluid needed to be a a certain temperature. Again, I think there's a way to get your car to tell you when it's at temp, or use a decent OBDII reader and look at the transmission temp.

TLDR; you changed the fluid so need to perform a TCU reset so the trans learns the new engagement points. The 01-04 I think has some self-learning capability so it'll adjust, but with 158k on the initial "learned" points you should have the TCU reset.

 

Maybe I'm being too literal, but what is the question?
I read a lot of explanation and self-pondering, but only one question mark.

 

Thank you both for the replies.

At the same time the fluid was changed, we also changed the battery so all previous learned data would have been wiped, I would believe. If not, then I will do it again.

The overfill lasted a few hundred km, most of it on the highway (85% highway runs is what I normally do)

I do have a dipstick so I am lucky I can do a D+F. I was not aware I had to have the car on and warm when doing the D+F. My understanding was that I measure what comes out first after it cools down and put the quantity-300ml and then warm the ATF, check dipstick and add in 50ml quantities as needed.

Should I go ahead and change the fluid with another simple D+F to keep cleaning the oil up?

I found this video and the part where he says that when he changed the fluid, there were a lot of particles where before there were none, really appears to be my case. My fluid was "clean but old" and when we did the D+F it became clean with particles. So my take is that the detergents in the new fluid separated a few things because of the quantity of fluid exchanged in the first D+F. So, I am hoping that the next one I do will take some of those particles away and perhaps the behavior I am experiencing along with them.

 

The info in this thread is becoming blurred between the A650E 5 speed w/dipstick) and the A761E (6 speed no dipstick).
Let's focus on your 5 speed A650E...
It does not matter if the fluid is cold, warm, or hot when draining and filling the A650E
No, the car should not be "on" or running during a drain and fill. Fluid will flow out more easily when the engine and trans are warm, but it's not imperative.
The engine and trans has to be at operating temperature when checking the fluid level after refilling.
Measuring the fluid that has drained out is worthless if you didn't accurately/correctly check the level prior to starting the process.
If the fluid was low to begin with, you measure what drained out then replace that same amount, you're right back where you started- low.

YT videos are a slippery slope of information and potential misinformation.