Should I change transmission oil even if Toyota says its not necessary on my 2007 Sienna?

Two dealers and my independent mechanic all told me that the vehicle uses “world standard” transmission fluid and NEVER needs to be changed. Never seems like a really long time considering I plan to keep this van for 200-250K miles. It has 122K miles now.

Should I:
a) leave it alone for 250K miles?
b)have it emptied and refilled now?
c)have it flushed now?

I have also considered sending a fluid sample to an oil testing service for $25 to tell me whether the fluid is too contaminated or has lost effectiveness.

I’d do the empty/fill (make absolutely sure the correct fluid is used, even if you have to buy some from the dealer), and repeat every 30-40k from now on. If you were selling next year, I’d say skip it, but since you want to keep it a LONG time, you’ll want to keep the transmission in top shape.

Toyota is like all the rest; they make recommendations that are good from a PR standpoint but no so good from the mechanical perspective. Transmission fluid changes, or lack of, is only one of those PR moves.

Unfortunately, a lot of mechanics even at the dealership level buy into ill-advised things like this.

If the car manufacturers feel so confident in fluid longevity then let them warranty the transmissions for the life of the vehicle…

My 05 Toyota 4runner and my wifes 07 Lexus say the same thing.

I still change the tranny fluid every 40k miles.

It’s well worth changing it every 40k miles. Cheap insurance if you ask me. Transmissions are expensive…changing the fluid every 40k miles isn’t.


My 2005 Camry has the same transmission as your car. I bought the car with 62K. I immediately changed the fluid and filter. I plan on doing that every 30K from now on.

I suggest you do the same.

Buy your fluid from the dealer.

DO NOT FLUSH THE TRANSMISSION. That could cause problems down the road. Not to mention that some shops that perform the flush use generic multi-purpose ATF and don’t even change the filter.

If it has never been done I would have the transmission drained and refilled, have the car driven for a few miles, then have it drained, have the pan removed and the filter replaced, then put back together and refilled. I would use only Toyota WS fluid. Couple hundred bucks now may help prevent or postpone a $2500 transmission replacement in the future.

Don’t do a flush. I think in most cases where the car is driven in a sort of normal way, it is still wise to change the fluid at 100K, and probably every 50K after that.

If you have a transmission dipstick, then this is a very easy DIY job. You will have a 10mm hex bolt drain plug, you drain the ATF, refill from the dipstick with WS ATF bought from Toyota dealer. Use some coupons from the dealer to cut the price down. If you want perfection, change the crush washer on the drain plug and torque it to specs (not sure what the torque should be). If at 120K miles this has not be done, then do it 3 times in a short interval and this should only leave 12% old fluid in.

I have a lot of respect for Toyota engineers but in this instance I have to disagree with them. Transmissions and transmission fluid have improved over the years but not to the point where preventative maintenance can be ignored. If they suddenly decided that engine oil changes were no longer necessary would you take their advice? Absolutely not.

Forget transmission flushes but do a drain and fill. I’ll go with the majority here and agree that 40K transmission fluid changes are the way to go. If you feel 30K is the number for you then I have no problem with that either.

If you have a transmission dipstick, then this is a very easy DIY job

Toyota seems to have eliminated tranny dip-sticks.

Also when you change the fluid it’s a good thing to change/clean the filter.

Thank you all for taking the time to answer my question. I will definitely get it drained and filled.

I read somewhere that Toyota, in recent years, is running their transmissions cooler than they have in the past.

If that is true, and I have no way to measure it, then it helps to validate leaving the fluid in there longer. Cooler trans fluid temps last much longer.

Why is @MikeInNH the only one, besides me, who recommends to replace the filter?

You wouldn’t want to change your oil and reuse the old filter, would you?

@db4690, I’m in agreement with you on the filter changes.

FWIW . . . I believe some guys don’t change the trans filters because the pan is sometimes “challenging” to remove.

On my 05 Camry the pan is a major PITA to remove. Toyota calls it a screen, supposed to be metal, but mine wasn’t. I bought one OEM from the dealer and same thing, it was felt. I looked at the old one and it was clean and clear. Granted, I started changing my ATF around 40K miles, the filter inspection was at 60K miles.
Due to the pan bolt location, I think I am just going to do drain and refill every 15-20K miles and skip the filter at 120K miles.

@galant Toyota has a tendency to call ALL of their trans filters screens.

My brother had a 1994 Celica, and I went to the dealer to get a trans filter kit. They had the pan gasket in stock but not the “screen” . . . according the the parts guy, the dealer mechanics never change them. They just get cleaned.

I said forget you guys and went to the local parts store and got a trans filter kit.

My 2005 Camry trans pan was also difficult to remove. But the filter looked awful and I was glad to be rid of it.

My 2002 Sienna has 193,000 miles on it, and still shifts smoothly. I drop 3 quarts and add 3 quarts every 20,000 miles or so, and it stays clean and sweet. I got this idea from the Cartalk Brothers some years ago. I have made the change to synthetic fluid.

I do not know if this is a good idea. i will tell you when the transmission fails.

I believe some guys don’t change the trans filters because the pan is sometimes “challenging” to clean

However failure of the filter can give you a good reason to replace your engine or car.

@JosephEMeehan well, if my trans ever fails, it won’t be because I didn’t service the ATF and filter in a timely manner.

That will happen to the other guys.

BTW . . . you quoted me incorrectly.

I said "I believe some guys don’t change the trans filters because the pan is sometimes “challenging” to remove

Almost every single trans filter that I’ve changed “on schedule” has looked absolutely terrible. None of them even looked remotely reusable.