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Changing Transmission Fluid in the 135i

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Changing the transmission fluid in the 6 speed manual 2009 BMW 135i is surprisingly easy to do.  In some ways it's even easier than changing the engine oil!

First we need to get the car up in the air high enough to climb under with some tools and a drain pan.  I use ramps with the 135i because my floor jack can't fit under the front bumber, but it can fit under the rear.  So, I drive the car up on ramps and then use the floor jack to bring up the rear so that it is level with the front.  Then I place a couple jack stands on the sides to be safe.


To jack up the rear - I use a wooden block to prevent any scratching.


Rear Jack 2

OK - we're done getting the car in the air and level.

135i in the air.

Now remove the center under panel.  These are 10mm bolts - just remove all of them.  There is a metal bracket or catch that holds the panel up, so when you're done removing all the bolts (think there were about 8 or so), turn the panel about 90 degrees so that it will fall away from the catch/bracket.

Under Covers

The fill plug and drain plug are both 8mm allen wrench (hex).  I used a tool like this one:

8mm Allen Wrench

The drain and fill plug are shown in the following picture.  Make sure you remove the fill plug first.

135i Transmission Drain and Fill Plugs

Get your drain pan in place and remove the fill plug, then remove the drain plug.  I let it drain for a good while, but the fluid is very thin, so it comes out quickly.

Click here for a video showing the fluid draining - not the highest quality video ever, but it gets the point across!  Got the tip from 'wolfe' on the 135i board to take a sample of the fluid to check for sediment etc..  I like that idea!

Drained fluid:

Drained Transmission Fluid

To fill the transmission, I used a piece of nylon tubing that I picked up at the local hardware store (Lowes or Home Depot).  It's 3/8" in diameter and fits very nicely into the fill hole.  I then attached the tube to a funnel using duct-tape to prevent any leaks of transmission fluid (which really smells!)

Funnel and Nylon Tubing


There is a sticker on the transmission stating that the fluid is MTF-LT-3 and that it is a lifetime fill.  Yeah - I just don't believe in lifetime fills!

Lifetime Fill

I choose to use Redline D6-ATF fluid as this is the recommended fluid by Redline.

D6 ATF Transmission Fluid

Insert the nylon tubing into the fill plug after replacing the drain plug.

Nylon Tubing - 135i Transmission Drain and Fill

The tubing that I used was 10 feet in length and I ran it over one of the exhaust pipes and then out towards the passenger side of the car to the funnel.  By holding the funel up high, the fluid runs in to the filler hole.  If you warm up the fluid before hand, it makes this process go a little quicker.

Funnel Fill - 135i Transmission

Make sure to keep the drain pan in place as you'll be filling the transmission until it starts to overflow out of the fill plug.  See how easy this is?  No need to worry about how much you're putting in, and no filters!

Filling 135i Transmission

It took about 2.5 quarts of fluid to refill the transmission.  Once you see the fluid dripping into the drain pan, remove the nylon tubing and let the remaining fluid drain out of the fill hole.  Then you will have a little bit of a mess to clean up!

Fluid Mess

I just cleaned it all up with a couple rags/paper towels.  All clean!

All Clean!

Then reinstall the fill plug and put the plastic under cover back on.  You're done!  Time for some twin turbo boosting!  I did notice that the shifter slides into gear more quickly with this fluid than before, and that it reduced some of the notchy feel of the shifter.

Last Updated on Sunday, 20 February 2011 20:10