[BlueB58]

I am currently going through the process of changing all the fluids in my F30 340Xi as it hits 60k miles. Having looked through several DIYs as well as the TIS, all of the sources I reviewed called for removing the transfer case support brace in order to access the drain/fill plug for the transfer case. This process adds significant complexity to what is otherwise a very straightforward drain/fill procedure.

Pic from FCP Euro showing the transfer case being supported while the brace is removed:


I went into the job thinking I would need to do the same (remove the transfer case brace). However, once I lifted up the car, I looked at the area around the drain/fill plug and noticed there was in fact a little bit of clearance. Not enough to use a 14mm hex socket, but just enough to fit a 3/8" coupling nut and a ratcheting wrench.



Here's the coupling nut you will need. It's close enough to 14mm to fit the drain/fill plug almost perfectly.
https://www.homedepot.com/p/Everbilt...2281/204337391

Here's a picture of what the contraption looks like from under the car. There's enough space for a 72 tooth ratcheting wrench to ratchet freely.



The drain/fill plug is torqued to 60nm (44 ft lbs), so you will need to apply a decent amount of force to the ratcheting wrench to loosen the plug. Once the plug is loosened, it comes out easily. After that, it's a relatively simple matter of siphoning out the old fluid, refilling using a filling pump or syringe, and then installing a new drain plug. I used a crowfoot socket with my torque wrench to torque the plug, but you'd likely be fine just using the same wrench used to remove the plug.



Hope you found this helpful!

[InstigatorX]

BlueB58 Thx for taking time to document the process. I’ll use at some point I’m sure.

On that note, what are the jack stands you used in the pics?

[Mkesler75]

Glad you found another way with less work. Fwiw I didn’t find removing the brace much trouble when on a lift, I could see how this would be much easier when not fully elevated. The exhaust hanger was the worst part and a few squirts of Wd-40 helped get the rubber hanger off.

[BlueB58]

Originally Posted by InstigatorX

BlueB58 Thx for taking time to document the process. I’ll use at some point I’m sure.

On that note, what are the jack stands you used in the pics?

Quickjack

[nh90crxsi]

Thank you much for this little gem, I used your method today!
Just a question, do you know about how much fluid you were able to remove and refill? I was only able to pull about 400 milliliters out/in the t case.
But it’s super easily so frequent changes won’t be hard.

Thanks again!

[claytonf30]

Originally Posted by BlueB58

I am currently going through the process of changing all the fluids in my F30 340Xi as it hits 60k miles. Having looked through several DIYs as well as the TIS, all of the sources I reviewed called for removing the transfer case support brace in order to access the drain/fill plug for the transfer case. This process adds significant complexity to what is otherwise a very straightforward drain/fill procedure.

Pic from FCP Euro showing the transfer case being supported while the brace is removed:


I went into the job thinking I would need to do the same (remove the transfer case brace). However, once I lifted up the car, I looked at the area around the drain/fill plug and noticed there was in fact a little bit of clearance. Not enough to use a 14mm hex socket, but just enough to fit a 3/8" coupling nut and a ratcheting wrench.



Here's the coupling nut you will need. It's close enough to 14mm to fit the drain/fill plug almost perfectly.
https://www.homedepot.com/p/Everbilt...2281/204337391

Here's a picture of what the contraption looks like from under the car. There's enough space for a 72 tooth ratcheting wrench to ratchet freely.



The drain/fill plug is torqued to 60nm (44 ft lbs), so you will need to apply a decent amount of force to the ratcheting wrench to loosen the plug. Once the plug is loosened, it comes out easily. After that, it's a relatively simple matter of siphoning out the old fluid, refilling using a filling pump or syringe, and then installing a new drain plug. I used a crowfoot socket with my torque wrench to torque the plug, but you'd likely be fine just using the same wrench used to remove the plug.



Hope you found this helpful!

how long did it take?

[johnung]

Maybe there is something different about the 340ix, because no brace needs to be removed to replace TC fluid in my 2015 335ix.

The Transfer Case has a lot of obstacles inside so it’s important to use a fine suction tip through the fill hole to suck out as much as possible. Move it all around inside. It only holds a liter so getting about 2/3 out is most one can hope for.

While you are at it replace front differential fluid too. It has both drain and fill plugs, and only takes one bottle. See photos.

[Nizzell]

Thanks for sharing !

How did you reset is afterwards?
ISTA ?

[gunnerxq]

Just did the job this way, probably the easiest if you're on ramps. About 500 ML came out. Recalibrated with Protool.z