volvo 850 AT drained 5+ qts trans safest way to refill?

[erikv11]

... OP, I' say keep doing what you're doing. ...

This.

It's a no-brainer. You must check when hot/idling anyway even if you do convince yourself to use some other method (right??!!!).

[cn90]

OK,

I did my experiment.

1- HOT engine and idle rpm, checked the ATF level: it was 3 mm Below Max.
It has been this way since the last time I changed the ATF a few years ago.

2- Next morning with COLD engine (engine OFF) and car in exact same spot.
Checked the ATF level, it is 3 mm Above Max "Hot Full".

So, my thinking is...
- When HOT, although the fluid expands in volume, some is pumped into the TC, so the level is a bit Below MAX as the book says.
- When COLD in the morning (engine OFF), although the fluid now contracts in volume, some is returned back to the sump, so the level is a bit Above MAX.

Anyway, this goes to tell you that it is fine to check your ATF fluid COLD in the morning and with engine OFF (on a flat driveway), as long as you know what you are looking at.
No need to warm up the car. If you have any doubt, do your own experiment, take photos (HOT and engine IDLE vs COLD engine OFF) and post.

[erikv11]

Ugh. See abscate's post. Yes we could do a bunch of experiments, by looking at many cars in many climates with various ATF fluids in them, various time intervals between checking hot and checking cold, etc.

Info from one car, one time, is potentially informative but presents a sample size of one and on that basis I definitely wouldn't go so far as to recommend to people "it's fine to just check it cold."

It's a cool idea, start a thread on it maybe it will get some traction, maybe it will even be true.

[cn90]

Just checked again with engine HOT and at Idle speed of 750 rpm.
I revised my post above to be accurate.

If you use the Max (HOT) as a landmark, in my case:
- Engine HOT and Running at 750 rpm: 3 mm Below Max.
- Engine COLD and Off (not running) in the morning: 3 mm Above Max.

The bottom line: the difference is about 6mm for these 2 situations.
So, if you want a quick check in the morning with engine COLD and OFF, 6-10mm above Max is good.

I sketched a little diagram so you can see what I mean:

Volvo-ATF.jpg (94.73 KiB) Viewed 2527 times

[erikv11]

Just checked again ... I revised my post above to be accurate. ...

Interesting, with this one car you didn't get the same readings one day to the next. Why did you delete the information for the first set of observations, and/or decide the second test was more "accurate" than the first?

So here is the story so far:
- by one test, the levels were exactly the same warm and cold (those observations were deleted)
- by a second test there was 6 mm of difference between warm and cold

Did you actually start with step 2 below (measured cold), then drive the car around, park it back in the same place, and measure again? If so maybe you want to edit again to fix this part, it is not really accurate:

...
1- HOT engine and idle rpm, checked the ATF level: it was 3 mm Below Max.
It has been this way since the last time I changed the ATF a few years ago.

2- Next morning with COLD engine (engine OFF) and car in exact same spot.
Checked the ATF level, it is 3 mm Above Max "Hot Full".
...

Maybe one interpretation here is to expect 6mm of variation on this one car, measured at this time of year, with this particular ATF - or something like that. More cars, more climates, more tests, etc, would start to paint a more complete picture.

[cn90]

Erik,

I revised my post b/c when I first wrote that post a few days ago, I went by memory from a few years ago.
What I initially wrote "same levels in hot engine vs cold in the morning" was not accurate, so I revised the post.
Anyway, instead of quoting me and going back and forth, you should do your own experiment and post back with actual photos.

Later on, I did the test myself with real measurements in the afternoon (going home from work with hot engine running) and again early in the morning at 7AM when I get up. Car in the exact same spot, the latest post is correct, the difference is about 6-10 mm.

[alschnertz]

I'm glad this information is not as complicated as the factory recommended procedure for checking the fluid level.

But, tHough some feel it cumbersome, I will stick to the factory recommendations and will suggest that others do too.

[cn90]

Actually it is not cumbersome at all as long as you make a sticky note (masking tape in the engine compartment saying "6-10 mm above Max is OK for COLD and OFF engine"). This way you don't have to memorize this stuff.

So let's say you get up in the morning with COLD engine (engine off), all you care is checking engine and ATF levels.
You check engine oil level, then...
You pull the ATF dipstick, if it reads 6-10 mm above Max with engine COLD and OFF, then you are OK. Nothing magical.

[abscate]

Whats up with this testing things multiple ways and then aggregrating data to draw conclusions? Is this some sort of new-fangled scheme someone has dreamed up in Iowa?? I might just be gaussing here...

[Sommerfeldt]

The only way you'd ever need some kind of sticky taped, millimeter measured ATF level notation in your engine bay is if you're worried about a sudden, catastrophic leak of tranny fluid while the car is sitting by itself. Barring that, you don't need to measure the ATF when it's cold, and so the factory method is definitely the best, easiest, least complicated and safest way of doing things. Like Erik says, to get any kind of useful reference, a lot more testing would have to be done.
Unless there's a big pool of something or other under the car, it'll always be safe to start it up and do it the Volvo recommended way. These aren't Hondas.

- S