Last May I got a 2005 4Runner, V6, 2x4 with a no dipstick, sealed transmission. When we got it it had 125k on the odometer and came with no service history since 2008.

So at 128k I took it by my local stealership to get a Toyota oil filter. When I was there the mechanics pointed out several things, one being that I needed to change my transmission fluid at 125K. They said waiting wouldn't hurt, and the service was about $250, so I waited.

So here I am at 130,500. I definitely don't believe in "lifetime fluid," and originally I figured it was a given to change. I don't want to damage my transmission by leaving it alone, but I also don't want to stir up sludge and damage it because of that. My question is this: Not knowing if this fluid has been changed ever, is it a good idea change this fluid (at 130k) or not?

I'd change it just to know it was done. The more I know the history of my runner, the better I feel about it.

I would change it. I struggled with the same question for a long time and finally just pulled the trigger and had the dealer do the exchange service. Now I know that it has fresh WS fluid in there for another 100K.

I'm in the same boat. 136,000 miles and have gotten different advice from independent Toyota repair shops and dealerships. Have been told by a dealership and an independent not to mess with it at all if I'm not having issues. One dealership said just a drain/refill. Another independent said a drain/refill is a waste of time because it's only a third of the fluid.

I'm being quoted between $300 - $350 for a flush.

I recently got a pop up camper and some long trips planned. Will probably just go ahead and get it done. But have also heard getting a 'flush' on an older tranny can cause issues because it loosens up crap inside the tranny.

Anyone ever get a tranny flush and have issues afterwards?

Probably not a FLUSH, but a fluid exchange with a machine at the dealer. Cost me $300 (about). Cheap in my opinion. I had it done at about 100,000. I'm at 115,000 now. No issues. In fact, I'm going to have it done again when the clock hits 150,000.

@JohnnyxRex : AT 128,000, you are overdue, but not RIDICULOUSLY overdue. I would change it. Even If you are having symptoms, I would change it (ATF). NOW, if you're tranny is at 350,000 miles with no change ever, then I would leave it alone.

Service History says Mine was Done at 55k. At 135k Now. I will do it again just for knowing its All Good. Mine is Not a Sealed Tranny. Nice to have the tranny Cooler too.

How do you fill it if there's no tranny dipstick? Sorry, i'm a lame 3rd genner just browsing the 4th gen section

How about a trans with 200k and never been touched? I'd like to change it for peace of mind, but I don't want to destroy it. Maybe a couple drain and fills? It shifts smooth, but I think it can run slightly smoother. Still better than my mother's brand new Ford Edge transmission.

I'd just do a couple of drain and fills. The old wives' tale of "if you change your ATF after X miles of not doing so it'll blow" is just that. Often times "old timers" think that changing the ATF after 150k+ miles was the reason the AT bit the dust, when in reality it was years/decades/10's of thousands of miles of neglect, but their confirmation bias allows them to believe it was indeed the ATF change that caused the transmission to blow.

If mine hadn't been changed in 200k I'd do a drain and fill, drive it around for a week, do another, rinse and repeat one more time and motor on. Then do a simple drain and fill every 30k or so to keep it running right for over 300k.

I agree, it's an old school thing that doesn't apply to the cars/transmissions/fluids today. I changed my 4th gen's fluid at 110k and again at 115k and it was totally worth it to me. Also, one thing that's few and far between on these trucks is transmission failures.

There is a fill port on the side of the transmission.

I have an 06 with 142xxx, with no record of any flush or drain and fill. I plan on doing 3 or 4 drain and fills this spring, summer and fall. 12qts on ebay is $107. Much cheaper than doing a $250 drain and fill at the dealership.

Thanks guys, I'm definitely going to change it. I've thought about dropping part of the transmission to change the whole 12qts and the filter. Eric the Car Guy has 2 videos of him doing it on a 2004 V8 (same sealed transmission) on Youtube. What I think I'll do though is just a few drain and refills myself. Is 5k a good interval between the first two drain and refills, or does it need more than 2?

I'm no mechanic, but I would drain/fill it at least 3 times. Someone correct me if I'm wrong, but a DRAIN only yields 4 quarts, right? So do the math (to theoretically exchange all 12 quarts, will take 3 tries based on 4 quarts each drain. In between each drain, I would drive several miles, I wouldn't wait 5K miles. That's just me.

I thought about dropping the pan and changing the filter as well but I don't want to drop the exhaust. You don't need to wait 5k between changes. You could do two drain and fills right away then maybe another 2 with oil changes. After that I would do it every 30k with diff./transfer case.