I did a cold transmission drain and fill and when i loosened the overfill plug about half a quart came out. The car was level and cold. When I refilled, i filled till it overflowed and then added back in a half a quart like it was when i drained it but I am concerned now about it being overfilled. Would you expect overflow out of a cold transmission? Vehicle has 90k on it and we bought it used, no information about whether the tranny was serviced so I did it as a preventative along with the oil and engine filter and cabin filter and spark plugs. I bought a belt but that project is on hold and looks like it's going to need pads as the inner pads are wearing much faster than the outer pads. Anyways back to the tranny. Would you get it up to temp and then let the overflow drain out? I am not excited to remove the wheel arch and using the leveling port but I can do that...i assume i just open that when the car is up to temp?

 

My preference is to drain the trans fluid when warm to hot as the fluid flows better when not cold.

I don't use the level tube unless there is evidence of a leak and the amount drained is significantly less than expected.

The F55 LCI 2019 will drain exactly 3.0 liters, I refill with exactly 3.0 liters.

I don't recall the exact temp required to use the level tube, I will guess it is likely near 40C. Note that one cannot use the level tube when trans is cold and the engine is off.

Further, be aware that it will require multiple drain and refill cycles to remove 90% or more of the old fluid. As I recall the 3.0 liters noted above is roughly half of the total fluid volume.

 

thank you...I will do a drain and refill and measure what comes out and go from there. If it is over 3 liters that comes out I will consider it overfilled and replace 3 liters. I will do this warm.

 

What model year and what specific model (F55? F56?) are we talking here?

 

2018 f56

 

6 speed automatic then?

If so, you have the same transmission as I do in my 2017 F56 S. I have done multiple fluid changes and I do them cold.

- In keeping with a previous reply, you'll get 3L max out during a fluid change but no more (presuming you don't overfill and drain out the excess of the overfill), and total capacity is about double that.

- Yes, some fluid will come out when you uncap the overfill plug, despite the car being cold.

Procedure for fill after drain is roughly (I'm noting this from memory):

(1) Replace drain plug but do not replace overfill plug.
(2) While cold, refill until fluid comes out from overflow. Note that it takes at least 30 seconds from pour-in for fluid to start coming out of overflow, so don't rush.
(3) Start car. Since you have to have the airbox off to get to access the fill hole/plug, yes this will cause trouble codes that have to be cleared at the end of the procedure.
(4) Shift car through gears P -> R -> N -> D and back again, leaving car in each gear for at least 2 full seconds.
(5) Let car continue to run until ATF temp reaches 35-45 degrees C. If you don't have a way to see ATF temp in real time, 15 minutes from the time you started the car should get you there.
(6) Fill again until fluid comes out from overflow. Note that it takes at least 30 seconds from pour-in for fluid to start coming out of overflow, so don't rush.
(7) Shift car again through gears as in step (4).
(8) Turn car off. Put everything back together again. Clear all trouble codes.

Hope this is helpful.

 

thanks, I believe i might have read your comments in a previous thread were you talked about going through the gears after a fill but i couldn't figure out if i should do that with the airbox off , firstly i didn't want to risk dirt getting into the intake manifold, but thanks for addressing that. It might not have been your reply but it was laid out very similarly.

 

Probably was my reply. I know I wrote up a step by step but it is deeply buried in another thread.

FWIW I did my most recent drain/fill less than a month ago. Running the engine with the airbox off is clearly less than ideal and I balked at it when I read it. That said, the source I read it in is BMW TIS, so that's about as authoritative as it gets. They are explicit about doing the gear shifting thing as well as getting the AT up to temp and the 2nd filling, etc., and it is literally impossible to put ATF into the transmission without removing the airbox (the fill plug sits underneath the airbox).

A bit not-my-taste but I figure BMW knows what they built...

 

ok thanks for your time I really appreciate it!