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      12-03-2012, 02:57 AM   #1
froop's Avatar

Drives: 08 AW 6MT E82
Join Date: Jul 2012
Location: Sydney, Australia

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Arrow DIY - 135i/N54 Steptronic Automatic Transmission Fluid Flush and Service

DISCLAIMER: I am not responsible for any damage to personal property or injury sustained from attempting the following. Remember, stay safe and if you have any hesitations in performing this, contact your local mechanic.



I know there are a couple threads already with some good information on changing the transmission fluid for our steptronic cars however I noticed that some were either not 100% suited for our cars or were missing a little bit of information. I therefore decided to make this DIY as comprehensive as possible, from start to the finish.

I did my service on the weekend and it was my first ever attempt.


I have an 09/08 build E88 135i with the 6 speed automatic steptronic transmission. I purchased the car in June 2009 and at the time I did this automatic transmission service (2 Dec 2012) I had driven just over 100,000kms. Everything was fine in the car up until I installed a Procede Rev 3 and took the car to the track shortly after, roughly at around 91-92,000kms. Since that time I'd noticed that I was getting severe jerking on the upshifts from 1->2, 2->3 and sometimes 3->4. Usually this happened on the standard 'drive' mode but I would notice it also when just using the manual steptronic mode. Basically it would feel like the transmission was delayed in engaging the next gear and there would be a delay in acceleration/power and then after 0.5-1s it would kick in very suddenly with a vicious jerk.

I had attempted resetting the Adaptive Transmission Control which helped, but didn't completely fix the problem.

General Information

Transmission: GA6HP19Z. It is a ZF 6 speed transmission.

Fluid Capacity: 9L (Total in the transmission and torque converter)

OEM Fluid: Shell M-1375.4. ZF Lifeguard 6 is the exact same fluid. The colour of the fluid is a clear/yellowish fluid slightly darker than cooking oil and similar in consistency.

According to the BMW Technical Information System (TIS) the ATF is a lifetime fill however ZF lists the life of their ZF Lifeguard 6 in the GA6HP19Z transmission as 100,000km.

Materials Required

1. 6 Litres of compatible ATF Fluid - Shell M-1375.4 (OEM) OR ZF Lifeguard 6 (OEM) OR Redline D4 ATF.

I have contacted Redline Oil and they stated that their D4 ATF is compatible. It also states on their website that it is compatible with Shell M-1375.4. ECS Tuning also includes this fluid in one of their kits.

2. 1 BMW or ZF branded ATF Sump Pan

There should be no difference between the function of these 2 pans. The only difference would be branding.

The ATF Sump Pan has an integrated drain plug, o-ring, gasket, filter and 2 magnets that are pre-installed. It is not necessary to buy these other things.

3. 1 Replacement Filler Plug

All kits appear to come with a new filler plug.

Where Can I Buy These Items?

Below are your options for kits. (Note that the prices I've listed are what's advertised on their websites on 3 Dec 2012). There may be others but I'm not aware of them.

The Californian Transmission Supply Company - US$238.03 (6 Litres ZF Lifeguard, ZF ATF Sump Pan, Filler Plug)

ECS Tuning OEM Kit - US$348.90 (7 Litres BMW Shell M1375.4, BMW ATF Sump Pan, Filler Plug, 4 replacement oil pan bolts)

ECS Tuning Redline Kit - US$193.28 (7 Quarts Redline D4 ATF, ZF ATF Sump Pan, Filler Plug)

I purchased the ZF kit from Klaus at The CTSC as it used OEM fluid and was well priced. Shipping prices were also very good over to Australia. He was a little slow to respond to emails however he was quite helpful and even refunded overpayment of shipping costs which was an unexpected but pleasant surprise.


Low Profile Ramps x 2
Jack Stands x 2
Floor Jack
Spirit Leveler
3/8" Ratchet
8mm Hex Socket
13mm Wrench
T40 Torx Head
5/16" Allen Key
3/8" Allen Key
Bucket/Catch Pan
Fluid Transfer Pump

Step 1 - Raising the Car

I chose to use 2 ramps and 2 jack stands for safety. I drove the front 2 wheels of the car up onto the ramps. I then used the front right jack point to jack up the right side of the car and put a jack stand underneath the right rear jack point. I then jacked up the left front jack point to jack up the left side and put a jack stand underneath the rear left jack up.

It is important that the car is level for the purposes of refilling the ATF Sump Pan. Use a spirit leveler or a similar app on a smart phone. As the fill plug is situated towards the back of the pan/car, if the rear of the car is lower than the front you may not be able to fill up the pan with the correct amount of fluid before it begins to leak out.

Remember, safety is key. If you decide to use 4 jack stands, put blocks underneath the tyres. Any type of jack (scissor, hydraulic, floor) IS NOT a subsitute for a jack stand.

Step 2 - Removing the ATF Sump Pan Dust Shield

The dust shield is held on by 7 x 8mm hex bolts as well as the bracket pictured. After removing all of the bolts, the dust shield must be rotated around so that the clips on the bracket fit through the rectangular hole and the dust shield will come off.

Step 3 - Draining the Old Fluid

I drained the fluid when the car was cold. It is probably better to drain the fluid warm (30ļ-50ļC) but I doubt there would be any difference. Beware it's not too hot as it can scald.

There is a plastic drain plug which uses a 10mm Allen head to remove. It is not very tightly torqued so is quite easy to remove but it clicks as it turns. Once it is out, the old fluid will come gushing out. Have a large catch pan or bucket ready to catch the fluid. I measured approximately 4.5L of old fluid.

The fluid which came out was a darkish brown and had a very thin consistency closer to water than oil. I got it all over my hands and it dripped off like water. It washed off very easily with soap and water and there was no lasting smell or oiliness once washed off. Feel free to use gloves if you wish.

Step 4 - Removing the ATF Sump Pan

The pan is held on by many T40 socket torx bolts. I didn't count exactly. Qbrozen estimated around 16 but I am certain that there are quite a few more, about 24.

Access to 1 of the bolts on the right side of the car is restricted by the dust shield bracket. This bracket is held on by 1 x 8mm hex nut and is easily removed.

Access to 3 of the bolts on the rear side of the car are restricted by a midpipe exhaust bracket. 2 sets of bolts/bushings must be removed from the bracket. Each set is made up of a bolt, washer, 2 hard rubber bushings and 1 nut/washer. This is done by using an 8mm hex/torx socket on the head of the bolt and a 13mm wrench on the nut. Unscrew the bolt/nut and remove both bushings. The bracket can then be pushed out of the way against the bracket it was bolted to. If itís too stiff, the midpipe end of the bracket may need to be loosened so that the bracket can be wiggled. All thatís required for that is an 8mm socket (I think).

Once all of the bolts are removed the pan will quite easily fall out. Be ready for this as there is still probably >0.5L of old fluid in the deep (filter) side of the pan. The drain plug is located on the shallow end of the pan.

Step 5 - Installing the New ATF Sump Pan (with pre-installed drain plug, filter, gasket, o-ring and magnets)

Lubricate the o-ring on the end of the tube sticking out of the pan with some ATF (old or new up to you).

Align the pan and ensure that the filter tube seats into the transmission correctly. If you donít fit it in properly, you will notice that the right side of the pan does not sit flush and you will be unable to screw in the bolts. Once seated correctly, proceed to loosely tighten all of the torx bolts. It is important not to fully tighten the bolts in one go in order to avoid putting uneven pressure on the gasket, resulting in a leak.

Tighten the transmission pan bolts in a diagonal alternating pattern and in several stages. On the TIS I could not find picture for the exact pattern, but I just started in the middle of one side and criss-crossed in a diagonal star type pattern.

Once all of the bolts have been firmly tightened over the multiple stages, torque them to 10nM.

You may also want to check that the pre-installed drain plug is torqued to the correct 12nM specification.

Step 6 - Filling with Fresh Fluid

You will first need to remove the filler plug. This is torqued to 35nM and is in a very tight location. The only way this can be done is with an 8mm allen key and a small pipe. A ratchet wonít fit. I tried using a breaker bar with a socket on the end but there wasnít enough clearance and the end of the breaker but just ended up resting on the ground. Iím sure you can try this if you are able to lift up your car higher. I ended up dismantling the Ďthroneí from my drum kit and using the pipe from that which was about 9-10Ē long. Once the filler plug loosened, just unscrew it by hand until it pops out. Thereís no fluid in the sump so you donít have to worry about anything spilling out.

Due to the location of the filler hole, will be unable to conventionally pour the fresh fluid in. You therefore have 2 options. Either use a funnel with a very long flexible hose, or alternatively use a fluid transfer pump. I opted to use a pump. Feeding the intake tube into the bottle of ATF and the output tube into the filler hole, just keep pumping in fluid until it spills out of the hole. It took roughly 3.5-4L until it started spilling out. Make sure to keep a catch pan underneath to catch the inevitable spillage.

Now you will need to cycle the fluid through the gears. You do not need to replace the filler plug for this step.

Turn on the engine of the car and with the foot held down on the brake, move from park, to Reverse, pause, and then to Drive. Now keeping the foot on the brake, cycle through gears 1 to 6 manually several times pausing for about 1 second between each gear. I chose to do it 10 times. Then keeping the foot on the brake, move it back into reverse, pause, and then to park. Leave the engine running.

Doing this step will help to warm up the fluid as well as cycle it through the gears. The optimum filling temperature is 30ļC to 50ļC (86ļF-120ļF). I didn't use any thermometer but it was enough to make the ATF warm to the touch. The ATF should not be allowed to go over 50ļC when filling. If it does, the engine must be switched off and the ATF allowed to cool down, preferably to 30ļ before recommencing.

Now with the engine running in park continue to fill the sump with more fresh ATF. I was able to get another 1L of fluid in before it started spilling.

Now cycle through the gears again as before and then attempt to refill. It started spilling almost immediately therefore I assumed itís at its maximum level. All up I managed to fill about 4.5L of fresh fluid.

As the new fluid had now mixed in with the old fluid, the fluid spilling out was slightly more brown than the fresh fluid however had the smell and consistency of fresh fluid.

Now that the filling is all done, put the new filler plug in. It is probably impossible to torque it to the exact 35nM specification due to the tight space so I pretty much guestimated how much force I used to undo it, to tighten it back up using the same 8mm allen key and pipe.

Warning: During this stage, the exhaust will become quite hot so be careful of accidentally pressing or brushing up against the midpipes.

Step 7 - Finishing Up

Clean up any mess youíve made including on and around the sump pan (important), re-install the dust shield and then lower the car back down

It would probably be a good idea to reset the Adaptive Transmission Control. This is done by switching on the ignition (but not the engine), holding down to the floor the gas pedal for 20 seconds, releasing the gas pedal, switching off the ignition and then youíre done. Itís disputed whether this works however a few people have tried this with good results including myself. (Thanks Dack for this one!)

Step 8 - Checking For Leaks

It would be a good idea to check the filler plug and sump pan/gasket for leaks after a few days of driving. The best way to do this is to raise up the car, remove the dust shield and then run a clean tissue, section by section around the edge of the sump pan and then around the filler plug.

If you havenít cleaned properly youíll probably just end up wiping up left over fluid from the mess of filling it up earlier which is why itís important to clean.

If you have torqued the sump using the correct technique and torque specification then it would be highly unlikely you will experience a leak but it is always prudent to check.

Conclusion and Follow-up

Since performing the service I've noticed that the transmission definitely shifts much smoother and dare I say faster. I have yet to notice any hesitation or jerking in upshifts. I have not experienced any warnings indicators or lights. I plan to do this service every 50,000km from now on.

Edit 5/12/12: It's been a couple more days since I did the service and not only does acceleration feel buttery smooth but I also feel quite a significant improvement in throttle to power delivery to the ground response.

Edit 10/12/12: I jacked up the car again over the weekend to check the fluid level and check for leaks. I also took some clearer photos whilst I was under there. I first removed the dust shield and checked for leaks. Everything was ok. I then preheated the tranny fluid by turning on the engine and let the car to idle for a few minutes, shifting through the gears a few times whilst checking the heat of the transmission manually by touch. When the fill plug began to feel a little warm I removed it and managed to fill the transmission with 1 more litre of fluid. I was able to fill up this extra litre for probably a couple reasons. I didn't use a spirit level and therefore my rear may have been lower than the front initially. Also, I probably didn't allow the fluid to properly warm up when filling the first time. This time I made sure to allow the fluid to properly warm up and I jacked up the rear of the car a bit higher when filling. I then re-installed the fill plug and dust shield and everything is still fine. Went for a spirited drive and did not encounter any issues.

Edit 4/4/16: Thanks Sasha4 for correcting the allen key size for the drain plug.

Good luck! If you have any questions, please feel free to PM me anytime. If thereís anything wrong in this write up, please let me know and I will fix it up as soon as possible.
Attached Images

Last edited by froop; 04-03-2016 at 07:55 PM. Reason: Added some photos and edited some instructions