You need to have the engine running when you are adjusting the fluid level. If you don't have the engine running, your fill will be several quarts low. I know this from experience. I assume the fill procedure is the same for the 8 speed. I have the 6 speed. You can double check using
Google
Eight speed guys, please correct me if wrong. I don't see why the fill procedure would be different- but could be wrong.
Did you have a recent transmission service or did somebody adjust the fluid for you before this happened? If the fluid is low and you went into limp mode that one time (or a handful) you might be ok. Even if the lubrication circuit loses flow intermittently there will still be an ATF film for a bit. Was the transmission acting funny before limp mode? If the mechatronic unit loses pressure of a couple seconds the transmission will change ratios randomly (act weird). It may act up a couple times before the computer catches it and goes into limp mode.
If not fluid level, I agree it could be something in the mechatronic unit. The solenoids would be the next thing to look at. Too bad you don't have ISTA+. It would give you a bunch of information about the mechatronic unit solenoids, adaptions, etc, but there is a learning curve to get it installed and usable. Maybe somebody on a forum near you could help you with it.
With the 6 speed, when the engine is running, fluid is being pumped through the system and the fluid level in the sump drops a bit so you need to have the engine running to fill the sump so the fill plug has drips or a slow stream at around 35C to 40C. Over 40C is too much. Shoot for 35C. The BMW procedures say between 30F and 40F, some people say 40F. I split the difference at 35C, which will wind up being a little more fluid than at 40C. The fluid expands as it heats and takes up more volume. Sorry if you know this; just trying to be complete.
02-13-2020, 03:49 PM
Linear Mode
