Use the stick.

 

1. Same amount is the safest way but not necessarily the easiest - say you drain at bottom, put back bolt, remove refill bolt start refilling and cannot put back same amount - starts leaking out. Make sure you read dipstick the right way - don't know how it's on H, but some cars read only with hot engine running in P. I'd measure drained oil even if using the dipstick

2. My experience with siphoning, the tube you get through hole has small inner diameter so it's very long to remove a few qts. Better do with slightly warmed transmission. Also, don't know how close to the bottom the tube can get to remove more oil. About half oil stays inside torque converter, cannot be removed. Need to drain again - I prefer spacing the 2-3 drains by a few months, so transmission has time to adapt to 1/2 fresh fluid. Also with fresh oil prefer driving it mostly city to have many shifts - this speeds up adaptation relearn for fresh fluid properties. If you drive old transmission with fresh fluid mostly highway long distances with little gear shifting, it may wear friction discs prematurely

 

With a dipstick I assumed you would check it after it's warmed up and been driven a mile or two. The thing about adding exactly what was drained is fine only when you know it has the correct level when you started.

 

What about what's in the torque converter?

I use to do a running engine open cooler line flush of the fluid on Fords.

 

That's the way any flush machine works. We run a line onto a graduated 5 gallon bucket and would add while it drains. Works great for a flush and if you want to do a clean we just add it and run it before we do the flush. Works great.

 

You can run the engine to empty the converter, but don't do this through the drain hole. On my older Volvo, car on ground, all trans plugs in place, I would disconnect the trans fluid cooling return line at the radiator (upper hose), insert tight a transparent hose inside rad hole, start the engine, have the fluid pumped out and watching until the flow would get 'bubbly' and stop the engine right away so the converter doesn't spin without fluid. Not sure how safe for the converter is this, though, it's risky but you remove most fluid at once. But mainly, it's not a good idea to replace the entire fluid at once on an old transmission. The solenoids are adjusted to old fluid, pumping all fresh will have solenoids work less optimal - until they have enough time to relearn - which may wear friction discs prematurely. Better replace no more than 50% fluid at once (I prefer no more than 30% for the first time on an old transmission)

See at about min 8:50 in the video (not my video). I don't know if this can be done safely on a Hyundai
Volvo V70 Transmission Flush. DIY Transmission fluid change - YouTube

 

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Better replace no more than 50% fluid at once (I prefer no more than 30% for the first time on an old transmission)
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Agreed. Learned a long time ago that a full-fluid flush has a tendency to disturb/remove old fibers, metals particulates, etc, that have settled into a high-miler's case gasket areas, and actually cause new leaks and slippage later.
Suggesting best to do a couple of drain&fills over a 15-20k mile period to refresh the ATF but dilute the new fluid's detergent action.

 

To clarify, I'm not aiming for a full flush here, just the standard drain/refill that lets you get some new fluid in there (usually around 5qt, I think) and then I can repeat the process a few weeks later.

I know I'm not going to be able to get all of the fluid out with the siphon, I'm just checking to see if it's safe to do and would be relatively the same as the drain/fill.

Assuming my car already has the proper amount in it (dipstick looks fine), logically I would assume that draining and then refilling based on the dipstick only would get me back to the same point - but you guys are the experts, which is why I'm checking.

So, again, assuming the goal is to have an equivalent of the standard drain and flush that doesn't remove all of the fluid but replaces about 5 quarts, would the siphon+refill through dipstick and measure based on dipstick method work? My siphon has little marks on it showing how much fluid I've pulled out and I would still keep an eye on that, so I'd know if I was adding way too much or little.

From what I can gather it seems like it's safe to do, but potentially not optimal.

The reason I'm asking this is also because I don't have four jack stands. Usually when working on the car I jack up the front or the rear and pop two stands there. I do have ramps, too, and I guess I could get the entire vehicle in the air but I've never been a fan of it. I can't explain why, it's just weirdness in my head. I'm assuming I would need the car level to properly drain/flush from beneath, so the siphon just felt like it would be easier as I can do it with the car on the wheels and on the ground.

 

you got it. i did it this way for years. mityvac, then you can see what came out, and put the exact same back in. repeat few weeks later. dont need to get it all out, and yah, most of it is in the converter. drain plug method too much work. throw in a bottle of lubegard, too. good stuff

 

Suck all you want out of it.

 

"She's gone from suck to blow!"

Copy of Spaceballs Mega Maid "From suck to blow!" - YouTube

 

Using the trans pump to pump out the old fluid is no worse than the regular pumping action.

 

everyone has there way of doing it. i like to let it gravity drane down when the fluid is only "cold" i would not recommend draining it "hot" reason being ATF expands with heat making the volume of ATF expand into more fluid with that being said it actually gives you a higher reading when you measure it hot vs cold in your measuring drane Pan. you will actually be adding a little more ATF because of it being hot. so drane it cold to be accurite

 

Cold thick fluid does not drain as easily as hot fluid. Cars here as generally received hot, and customer is waiting in lounge for service. Drain it, fill it, and run with it. Customer is waiting

 

i like to let it gravity drain down when the fluid is only "cold" i would not recommend draining it "hot" reason being ATF expands with heat making the volume of ATF expand into more fluid

...if you don't mind waiting, let it cool down after you drain it and get your accurate measurement. The best of both worlds! Both fluids (oil, ATF) should be drained hot.

 

Engine Oil is a tad more forgiving as far as heat affecting the Oil level goes ATF on the other hand once hot it is not forgiving at all oil volume increases with heat. wich is why? im more of a cold drane & fill guy on the ATF Just saying its what i do & prefere doing on my Santa Fe & daughters Elantra as far as keeping it filled correctly with proper ATF from Hyundai Manufacturer like day 1. again everyone has there way of doing things.

 

I do it as the manual says...then I'm not guessing or measuring. Note: you can start with a measured amount if it's about 4-quarts, then use the manual's instruction for the proper level.