When the pan temperature reaches ~104, you pull the fill plug. Extra fluid will run out. When it slows to a drip, reinstall the plug and you are finished.

 

I'm guessing you would need a laser heat gun for that correct?

 

Probably the easiest option and they're only about $10.

 

Awesome thank you as always blnewt

 

lol, your reply was so quick that I couldn't edit it, those infra red guns are even cheaper, like $9.95 at walmart and you can re-use them

I just borrowed one from a neighbor (didn't know they were that cheap) took about 5 minutes of the engine running to get the temp at 103-104.

FWIW, this posting from davison is pretty good, there is some flexibility regarding that temp window, I wouldn't get too crazy over it.
https://www.myg37.com/forums/d-i-y-i...ml#post3911189

 

Very pleased with the transmission and shifting after the replacement of the fluid. Shifts are very smooth and crisp. I had been looking to do this for some time but after speaking with the dealership and not seeing any information that helped me understand this procedure, I had resigned myself to the "sealed unit" dealership speak. The car has 95,000 miles and the transmission shifting had become very noticeable. I had even noticed what I perceived as slippage.

 

Glad it worked out Mach, the dealerships really can keep you in a fog regarding this particular service, glad you had your fog lights on

 

Hi David, do you have to replace the gasket or reuse old one and also when you fill the trans fluid through the fill hole or return line from trans cooler?

Thanks,

 

I still haven't changed my tranny fluid yet, but plan on doing it soon before the winter. I would like to know that as well. I don't wanna have to go to the dealership for a new gasket mid way haha :P. Also what if the ATF doesn't reach the right temperature?

 

That OEM gasket is a good one, not the type that will stick to the flange and peel apart, it's a solid piece of rubber. I doubt there would be a problem removing it as long as you don't try to get it free w/ a blade. I imagine there are cases where it could be hard to remove (if the trans was overheated/abused) but under normal operation I don't see removal & reuse a problem.

As far as the right ATF temp, those infrared temp guns are good and doesn't take long to get that ATF temp close. Doesn't have to be exactly at 104, a couple degrees either way won't make a noticeable difference in fluid volume.

 

If you dont have an IR thermometer, just get some of those sticker thermometers and put 2 on the pan in different locations.

 

Ok, I have read the diy and have three gallons of the maxlife atf ready. Car is up on my quick jack and i have looked at the pan (24 bolts, drain plug and overflow plug). I have looked at the pics and can't find the "fill plug". I have done this service on all of my BMWs and the plug was always on the side of the trans. I am just not seeing it on this one. Am I supposed to use the overflow hole in the pan (drivers front corner of pan) and that is why you need the plastic fitting? Going to go change the engine oil/filter and hope I get a quick reply... Thanks!

It is a 2011 4dr 37S with 7AT (that shifts like ****) with ~65k miles.

 

Tube at lower left is the fill, the other plug is the drain

 

What you are referring to as the overflow hole is the fill hole. The adapter makes life much easier.

 

Yeah, I had a cone shaped plastic adapter left over from a brake vacuum bleed kit that I made work with my fluid pump. Just seems like a poor design, a quart and a half drained out when I first pulled the "fill plug". You would think they would have made the tube tall enough that when fluid stopped coming out of that plug (overflow) that it was set at the right level for the tranny.

Three drains of a gallon each time and at least it was reddish the last time. Will probably get another 3 gallons and do it again with the next oil change since the fluid is so cheap from Walmart on-line (~ $18/gal delivered for maxlife).