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Drain & refill trans

Just did the second drain & refill after 30,00 miles on the first. On the first one, I did the recommended 3.7qts abut had to ad about another qt. to bring ity to the full mark on the dipstick. Have read here since then that on a drain & refill you can only drain the 3.7qts and that should be the amount replaced. This time, I added 3.7qts. and again did not reach the full mark. I decided to leave it, went on a 800mile trip, trans shifted perfectly ( as it also did the first time ), averaged 25mpg. I have never been able to get an accurate reading on a dipstick, ie no clear level mark, always an irregular showing. Question is, should I rely on the 3.7qts. or add to bring it up to the full mark. The vehicle is a 2004 Sienna.

No. You should rely on the measuring tool (dip stick). I had the same issue with my Accord. My transmission fluid was good and hot when I drained it, and maybe that helped drain more fluid. I put in the prescribed amount for a drain and fill, cycled the fluid on short drive, then checked it. I needed a bit more just as you did.

Check the owners manual for the correct method of reading the level. On GM you need to bring it up to operating temp and run it through the gears, then check while on level ground while in neutral. Some you check not running, etc. Temp does make a difference though, but read on the dipstick. Of course on my Pontiac, I don’t have a dipstick or an easy fill point, so take it to the trans shop.

“Of course on my Pontiac, I don’t have a dipstick or an easy fill point, so take it to the trans shop.”

We have the same thing on our 2009 and 2010 Cobalts. I’m disappointed that GM chose that route. The caution in the owner’s manual is if the transmission starts acting up to take it to the dealer for service. That seems rather late to me; the damage is already done. Is the transmission fluid supposed to last forever? I doubt it.

Back on topic: Good points, Bing. You have to put the car in the correct configuration to check the fluid level.

Make sure you read the owner’s manual on how to measure the ATF fluid reading. Every car is different. Often you have to bring the car to operating temperature, and then shift through all the gears, holding each for a certain amount of time. If the procedure isn’t followed, you can get an inaccurate reading on the ATF dipstick. If you feel the dipstick level – even after following the procedure – is ambiguous, take the car to the dealership and ask someone there to show you how to read the level. Try to go there at a time when they aren’t busy, like early in the AM, not just before they close. Usually – as long as they have time – they will do this for free, as a customer relationship service.

Bing, GM vehicles are to be checked in park . I think you are thinking of dodge alot of those are to be checked in neutral and i have never seen one that you check not running but then i dont claim to have seen it all. Not hating just saying. As for the cobalts and some other gm vehicles w/o a dipstick they have a plug underneath on the passenger side by the axle that you can remove and if fluid is to the bottom of the hole it is good. But you do need a way to get under it with it running and level to check which usually involves a rack which i realize most people dont have at home. As for the OP your manual will tell you that all fluid capacites listed are approximate and to check the level and add as needed. Alot of dipsticks do have a cold mark as well as a hot mark.Now as for me if i had to be overfull or a little on the low side I would choose to be a " LITTLE" on the low side because as you are cruising down the hwy at 75 mph it is gonna get hot and expand. And i do mean just a little and not any to be found on the dipstick low, that would be too low.

g-14classified wrote:
I think you are thinking of dodge alot of those are to be checked in neutral and i have never seen one that you check not running but then i dont claim to have seen it all.

My 2005 Acura MDX is checked with a hot transmission but the engine off.

Well thank you lion9car i will keep that in mind as i said i dont claim to have seen it all.

I believe Honda CVTs are also checked hot with the engine off.

Yea, Honda has this instruction about warming up the car/transmission, shift through gears, put in park, turn engine off and then check the level 30-60 seconds afterwards. I believe that for your regular driver, that is a bit over the top.

ZF transmissions are checked differently than GM’s. But I understand there are some ZF’s in some GM vehicles. Read your book.

Les

George wrote “Make sure you read the owner’s manual on how to measure the ATF fluid reading.”

Good luck with that when it comes to Toyota’s. Its not in the owners manual or even in the factory service manual, but it is read with the engine off. The dipstick has two notches on it, one for cold and one for hot.

always trust the dipstick.

Good luck with that when it comes to Toyota's. Its not in the owners manual or even in the factory service manual, but it is read with the engine off. The dipstick has two notches on it, one for cold and one for hot.

And now many of the newer Toyota’s don’t have a dipstick.

This isn’t the best method but it works for me. After the car has set overnight and with the engine cold and off, I check the level on the dipstick. Then, I drain the transmission and refill it to the level it was before I started. Then, I start the car and drive it a short distance and recheck the level. Takes the guess work out of the equation. Another method that works is to drain the transmission and measure how much fluid came out and replace it with the exact amount. Draining and refilling it cold doesn’t get as much fluid out as doing it while warm but, if you do it often, it doesn’t make much difference in my opinion.

I am always happy to learn new things, i did look up the honda and acura procedures and they do say to check with engine off . thats cool i said i havent seen it all. but i have yet to see a gm transmisisson you check this way 42rangie.your " read your book" comment sounds like you are trying to turn this post into a pissing contest which isnt what this forum is for nor does it help the OP with his question. But please enlighten me.

My granddaughters 2003 Saturn Ion puports to not have a dipstick and the owners manual claims the fluid is good for the kife of the car. She has had the car 2 years and it has 103,000 miles on it.
It was slipping and sometimes refused to upshift.
I found out it has a “hidden dipstick” that you have to remove an odd size metric bolt low on the engine to axxess.
Changed the fluid and it started shifting better. A month later it shifted as good as new.
“Good for the life of the car” my foot.