Hello all, I'm here hoping to get some sense of whether or not I want to get a transmission flush and fill on my 4 Runner. It's a 2010 SR5 with the 4.0 engine and has approx. 87K miles on it. I know in the past there have been two very different schools of thought on transmission flush & Fill services. But I was wondering if there were any new schools of thought that would influence me one way or the other. While I do not believe that any fluid is "lifetime", I also don't want to risk having a transmission slipping because I did the service. If forced to make a decision this minute, I would be leaning away from having it done as the transmission seems to be shifting flawlessly, and as my dad used to say " if it aint broke don't fix it ". On the other hand I want to do whatever I can to insure the smooth operation of this vehicle as I intend to keep it another 4 or 5 years since it only has 87K miles on it. So you see, I'm kind of caught right in the middle. and it doesn't help that I called 2 toyota dealerships today and 1 said don't do it, Toyota doesn't recommend it, the other dealership said to absolutely do it. Anyway, I would appreciate your thoughts and opinions on this. thanks in advance.

Isn't the best thing to do to just drain and fill and change the filter? Flushing should only be used as a last resort from my understanding. Not an expert.

I wonder why a dealership would say dont do it...especially when the owners manual specifically gives a mileage number of when to do it. Maybe 'flush' means something different than 'drain-refill' to them. Maybe someone can teach me the diff as well...

Owned since new, I had mine done at 110,000 miles. I wasnt having any problems, no slippage, no issues with 4WD or offroading or in snow. I just figured it was time (per the manual) and i got it done...flush, filter change, and refill. and i havnt worried about it since. I plan on doing it again at 200,000.

on some level, Toyo does say this is a 'sealed' transmission...however, if thta were the case, why is it so easy to empty and refill it?

this guy seems to be credible on some level
Toyota 4Runner Transmission. Why is it so reliable? - YouTube

he has a whole series on the T4R...
The Car Care Nut - YouTube

adding to that...on other posts
Fluid Change Interval

where it is pretty steady in people learning/saying do it at 100K.


hope this helps

ATF Exchange (using the cooling line)

Transmission Fluid Change procedure

Transmission Fluid Change procedure - Toyota 4Runner Forum - Largest 4Runner Forum

Yeah, several other threads on this you can review for opinions.
I posted my change (drain and fill) in the thread mentioned above.

Transmission Fluid Change procedure

@d4vid made a great vid and linked to it in the thread as well.

There’s also one in the 4th gen thread with some people going over 200k on the original fluid.

How many guys are still on original transmission fluid? Come on in!

The official maintenance guide does not have an interval for normal use. I do not see 100k mentioned for replacing automatic transmission fluid, only inspection every 30k, and replace for “special operating conditions” service at 60k.
See for yourself.
https://www.toyota.com/t3Portal/docu...MG_0W20_lr.pdf

Personally I would do at least one drain and fill to check the condition of your fluid, it’s probably similar to mine when I changed last year.

How many original miles? Want to sell your truck?

I’ve done it and used Valvoline synthetic ATF. 2014 SR5 which now has 260K miles and is past due for another flush. I will be doing it soon. No issues.

Don’t believe the Bullshit stories about flushing transmission fluid dislodged all the junk holding it together, causing the tranny to fail shorty afterwards. These are the same guys who believe you must use OEM Toyota Fluids.

Don't flush. Flushing is a forceful pressure that will stir up sediment that may later clog things up. Just drain, replace the filter, and refill.

Toyota does recommend replacing the transmission fluid if you have any driving that stresses the transmission, such as trailer towing, off roading, etc. Otherwise, the transmission fluid is considered "lifetime". Why they recommend that is due to the heat generated during those activities; heat is always bad on oil. Thus, you are wise to replace the fluid from time to time even if you do not stress the transmission.

On my Tacoma, I had the dealer flush once but I used the cooler line method each other time every 50K miles.

I remember when Toyota called it lifetime fluid then changed it to 100K fluid.

Here we go with spreading the transmission flush wive’s tales. Forceful pressure dislodging sediment? If you had ever gotten your pretty nails dirty and done a transmission flush, you’d realize this is technically impossible to occur. To flush the tranny you simply detach the return line at the transmission, turn the engine on and pump out a couple quarts, turn it off and add a couple quarts. Lather, rinse repeat until the fluid you pump out is clear. So there is no "foreceful pressure" other than what occurs normally, oh and you do this with the filter in place which is what traps any sediment in the first place.

The procedures described on this forum to change 12 qts of fluid is not a pressure flush. The proper term would be fluid exchange. Fluid is pumped out at engine idle speed, at a leisurely rate.

Have you ever performed a panic stop? Have you ever floored the accelerator to get merge or pass? What happened to the fluid in the transmission pan? It sloshed forcefully to one end of the pan and then back and forth. Did this stir up any fine stuff that coats the pan and mix with the clean fluid? Your transmission is still working fine. A fluid exchange is far less "forceful" than a panic stop or rapid acceleration.

If you don't think you want to change the fluid yourself, then let the dealer do it.

I used to believe that these long life fluids would last 100k easily. Now I truly believe that you should do ATF as soon as your powertrain warranty runs out. I changed my fluid at 75k and wished I did it at 60k. The difference between 75k old fluid vs fresh valvoline maxlife was a major improvement in shift quality.

I flushed mine at around your mileage at the dealer a few years ago and it's been fine ever since. Recommended it for the hard off roading I was doing at the time.

No fluid is lifetime. But I wouldn't flush it. Have them do their regular trans drain and fill "trans service". I have mine done every 50k. If it makes you feel better, do it another time at 100k. My dealer charges like $199 I think. It's not expensive. If you really want all new fluid, have them do an exchange, but not a power flush.

Patrick, thanks for the reply.... as I stated originally, one local dealership said they don't do it because Toyota doesn't recommend it. Can you tell me where in the manual it says do it? I've been looking and haven't found it. Also, I think some people confuse what I"m calling a transmission fluid flush.. I guess in actuality it's a fluid exchange. The one dealership here that is recommending it uses the BG Power Flush Service is a fast, efficient exchange of your vehicle's transmission fluid. They claim It removes the old fluid and replaces it with new, clean transmission fluid in as little as 5-7 minutes, making it one of the fastest and most efficient flushes on the market.