[d4700]

Figured I'd post this since I didn't see any guides online specifically for the hybrid variant of this transmission. The job is mostly the same if you've done it on any other 6HP or 8HP, but there are some unmentioned oddities I've found in this process that I thought I'd share here.

The pan I used is a Hengst unit I got from RockAuto for $110+$16 shipping. An excellent deal. I used Valvoline Extended Protection ATF (Using the "MaxLife" ATF/CVT fluid makes me a bit antsy. Why would I want steel-steel friction modifiers in my step-shift auto?). My transmission took in a little over 6 quarts, so it's not a bad idea to just buy two gallon jugs of the stuff.

CAUTION - HIGH VOLTAGE. Do NOT work on your car while it is charging. Do NOT mess with any bright orange cables or modules with the caution tag on them. Be careful with your tools. BMW insists that you disable the HV system before carrying out this job, so you should do that.

1. Level your car on jack stands. Remove the handful of 8mm bolts holding the service tray directly below the transmission. Remove the tray and toss it to the side. Make sure not to lose any of the white plastic bits that clip onto it.

2. Open the fill plug slightly. It's to the right of the drain plug, next to the exhaust pipe. You'll need a stubby 8mm hex key to do this - I just used my Dremel and shortened the head so that it would fit. It's tight! We're just trying to make sure you can get it loose before you drain the fluid, so don't pull it all the way out yet.

3. Now open the drain plug. It's a 10mm hex. Have a big pan ready, it'll fan the fluid out into a pretty wide pattern. It's not a bad idea to measure the amount of fluid that comes out to make sure you're on the right track.

4. Remove the 15 or so T40 bolts holding the transmission pan up. It's a good idea to have an oil mat or some cardboard set down on your garage floor here, as this can get messy. Pull the pan straight off and make sure the O-rings on both of the pickup tubes came with it. Now just look at all that gunk!

5. Get your new pan and oil the O-rings for the e-pump and mechanical pump pickup tubes, just to make sure they slide in nice and easy. Push it straight up and, when the pan is flush with the transmission and lined up with the bolt holes, you're good to go. Don't force it!

6. Following this torque sequence, first hand-tighten the bolts, then torque them down to 10nm (~88 in*lb).


7. Once the pan is on, remove the fill plug and pump in some ATF until it drips out. In my case, it took about a gallon. This is your first fill.

8. Get in your car and start it in electric mode. Let it rest for about 10 seconds, then select D, then R, each for 10s. Make sure the parking brake is on and your foot is firmly on the brake. This runs the electric fluid pump. Shut off the car.

9. Get back underneath and pump in more fluid until it drips. I think mine took in another quart.

10. Last step - open your hood, then start the car. The engine will run. Get underneath and fill the fluid until it drips, and once the fluid is between 30-50C (as read through OBD port) and dribbling out, close the fill plug. Shut off the engine.

11. Nice work! Wipe off all the excess fluid, check for leaks, and put the service tray back on.

[nonford]

Appreciate your time and posting! Always good to hear the experience.

[letsbepolis]

Just to confirm, the pan is different from the normal zf8 kits?

[d4700]

Originally Posted by letsbepolis

Just to confirm, the pan is different from the normal zf8 kits?

Affirmative. On PHEV models the pan shape is a bit different (there's a sort of overflow reservoir toward the front of the car), and the filter has an extra pickup tube for the electric fluid pump.

[letsbepolis]

Originally Posted by d4700

Affirmative. On PHEV models the pan shape is a bit different (there's a sort of overflow reservoir toward the front of the car), and the filter has an extra pickup tube for the electric fluid pump.

I ordered the same Hensgt unit, funnily enough they make the ZF branded ones also! I will be following these instructions for my 330e G20, thanks loads buddy!

[d4700]

Originally Posted by letsbepolis

I ordered the same Hensgt unit, funnily enough they make the ZF branded ones also! I will be following these instructions for my 330e G20, thanks loads buddy!

Glad you found the writeup useful! Hope it goes well.

[letsbepolis]

Originally Posted by d4700

Glad you found the writeup useful! Hope it goes well.

Buddy if you don’t mind me asking, what app did you use to measure the fluid temp? I am struggling to find one that shows transmission temp?

[d4700]

Originally Posted by letsbepolis

Buddy if you don’t mind me asking, what app did you use to measure the fluid temp? I am struggling to find one that shows transmission temp?

I use BimmerGeeks ProTool. It has a somewhat high upfront cost, but I've found it to be well worth it for coding and diagnostics. It's a very powerful program.

BimmerLink should work well too, but I haven't tried it to confirm.

[letsbepolis]

Originally Posted by d4700

I use BimmerGeeks ProTool. It has a somewhat high upfront cost, but I've found it to be well worth it for coding and diagnostics. It's a very powerful program.

BimmerLink should work well too, but I haven't tried it to confirm.

Rough idea how long it took to get to around 30C?

[d4700]

Originally Posted by letsbepolis

Rough idea how long it took to get to around 30C?

When I did this in January, I think it took maybe three to five minutes starting from cold. My outside air temperature was around 18-22 degrees C back then if I had to take a guess.

30-50C is a pretty wide margin. It wouldn't be hard to get a good fill by ballparking it, especially on a summer day where you're already starting out at 30C and you can fill it immediately. The temp doesn't rise very quickly at idle.

Remember we used to do this by looking at a dipstick with a huge margin between "min" and "max," and no idea how hot the trans fluid was - just "hot enough" since we'd been driving it for a while.

Even if you're just estimating the temperature while filling these ZF boxes, it's still far more precise than the old-fashioned way of doing things.