Sorry, I wrote a reply and then actually read this thread. Yes, do a full fluid exchange. It sounds like your transmission is just starting to have issues. I think it will be alright doing the full flush.

 

I am about to have some parts installed at very well rated import shop & I am considering getting my transmission drained & filled on my 07 IS250. She doesn't run bad, she is just a little sluggish but I do believe she has carbon build up issues which may be contributing to sluggish acceleration.. When I go from park to reverse sometimes it will skip R & go straight to N but sometimes I feel like it could be my fault early in mornings when I'm barely awake haha. She idles at little weird sometimes too lately. Occasionally, I'll be at a red light & she'll start to idle up and down & then it almost feels like the car is bout to run out of gas & turn off as it starts to shake a little... I have not had anything transmission work done since I got the car @ 89K, now at 170K, so I imagine I am overdue for a change.. I am pretty young & learning everyday as I go, so definitely playing catch up on my maintenance. I will of course ask the shop but I value everyones opinion on here.

 

Yeah, what you're describing there is likely carbon build-up issues. Ask the shop how much it would be for a walnut blasting (assuming they offer such a service). If they do not offer any sort of service where actual media is blasted onto the backs of the valves, then go somewhere else for that. If they say they have a fuel treatment service, more than likely it's a treatment in-a-can that won't give you the results you actually need.

Yes, look into getting your trans fluid replaced BEFORE you encounter trans issues. Preventative maintenance FTW!

 

I come from an ISF, unfortunately mine has been slipping as well. did the level procedure and a fluid + filter change and still slipping at some points but does feel better. i recommend servicing it. no fluid is lifetime. bust of luck!

 

Had you ran low on fluid due to a leak OR was it just the original trans fluid that began to create the slipping issue? Hope the slipping completely goes away; many times when a trans starts slipping the internal parts glaze over from excessive heat/wear and no amount of fresh fluid can fix that.

 

I just bought the car at the end of September, so your guess is as good as mine about the life the transmission had. when i did the level set procedure the other night, fluid came out looking like it should. thats about all the info i have.

 

Did the fluid smell burnt?

 

@Gville350 @2013FSport So I just got my 250 back today from having the transmission drained & filled &... The car feels funny. So like I said before, I wasn't sure there was any issues with my car before the flush. Upon receiving car from shop & driving it, I immediately noticed some "stiffness" I guess you could say. It feels like the car needs a bigger push to get up & going. I tried the sport mode using the my regular shifter (my - paddle shifter stopped working month after buying car, so dont use em) & sport mode definitely seems more responsive than before but still not how I think it should be working. What really worries me is the guy whom I spoke to at shop said he was very familiar with the toyota system since he has 2 toyota's himself but upon looking at the receipt he gave me, I immediately felt like I should check if he used the correct fluid. I found out he used " ENEOS ECO ATF FLUID" # WP-399571, I looked it up & saw that its "compatible with Japanese's vehicles but still... wouldn't it have a different viscosity or something that wouldn't mix correctly with the original toyota ATF fluid..? So I'm pretty worried & would like to know what you guys think. Thanks !

 

It's probably a better fluid. Toyota WS fluid is a synthetic blend whereas Eneos claims to be a full synthetic. Supposedly, Toyota WS fluid was created so that Toyota would have to pay less taxes for the vehicles they sell in the US due to its longer service interval. Exxon/mobil makes the fluid for Toyota.

 

You could disconnect the battery and let it relearn and see what it does? Their site says it is fully compatible but seems to not have much detail. After reset, let us know what it does. Provide some details.

Sorry, but I can relate to your words about it needing a bigger push. Can you elaborate?

 

@firelikeiy I do agree & see that ENEOS seems to be advertised as a better fluid but being at 170K miles, its pretty late in the game to start changing the type fluid the car uses I would think.. & they didnt change the filter, just a drain & fill to introduce new fluid.
@2013FSport After testing the car for a few days, the car is doing a little better but, for instance, usually, I can step on the gas/floor it & the car will immediately pick up & go. From 20 - 50 no problem, now... (ive tested this a few times) From a complete stop I floor it & the car pretty much goes nowhere.. it just slowly pushes itself & it takes like a minute or two to just hit 40's. Even from a 20 MPH roll, I floor it & again the car pretty much goes nowhere,no quick acceleration, no power at all.. if that better describes my situation. We are dealing with snow now in CO, so wont be doing any more tests till roads are clear, but I'll do my best to remember to record a test run when the weather clears up & post the video so you have a better understanding of what I am describing

 

Just asking the obvious but the car isn't in snow mode is it?

 

@firelikeiy haha no, I made sure of that. I got the car back days before any snow arrived in CO, so no reason for snow mode to be on.

 

@Moisture - I just bought a used 2006 IS 350 w/ 124K miles on it. I feel like there are times where the transmission starts to slip a bit based on what people in this thread described. The last owner was pretty good about maintenance and got the transmission fluid done at AAMCO. Nonetheless still feel like it may be a little slow to respond, especially from a cold start. Could it be something else that's causing this issue? It seems this car has a tendency to shift up rather fast - I'm usually in 5th or 6th gear by 40-50mph+. That said it doesn't downshift as frequently, I'm usually still in 5th gear even if I slow down to ~20 mph or so. Is that normal?

 

Does the transmission filter have 1 or two O rings? When you replace the filter inside the transmission sump pan, lets say god forbid the rings fail or didnt seat correctly. Seeing as the filter is inside the transmission pan and then sealed up with the transmission pan gasket, you will never actually see if those rings fail and if the filter O rings leak. What will be the consequences of that? I get a bit paranoid about O rings and things that sit inside. The ones that you can check externally at least you have the peace of mind that you can visually inspect it.