Transmission oil change on a Rex from 2016 onwards

[Nigel200]

What do you have to do to locate the upper vent port for refilling the transmission oil?

There are a lot of electric cables and hoses obstruction access. So if I remove and disconnect the electric cables will the be issues when I reconnect them?

Thanks in advance for any assistance.

Nigel

 

[Pipino]

Hi Nigel,

Did you find the solution? I am also looking into changing the transmission oil on my 2015 rex (without filler plug).

Thanks,

Pipino

 

[vodkag]

Same question here 2017 with REX but cant get to the air vent with the REX in the way......

 

[nilknarf]

Add me to the list of rex owners without a fill plug (2017). Bumping this thread in case anyone with a rex has figured out how to get to that breather vent. I was wondering if maybe you could reach it from underneath, attach a tube and feed the tube up through a gap?

 

[nilknarf]

Found this video where someone changes the transmission oil in a newer rex by pumping oil into the drain hole, then he immediately rips out the hose and inserts the drain plug. He added a little extra oil for spillage.

A cleaner way of doing this with an accurate fill would be to install a quick twist oil drain valve: https://www.valvomax.com/products/quick-twist-oil-drain-valve

We'd need to determine the size and pitch of the existing drain plug.

 

[nilknarf]

Someone also indicated on bimmerpost that they filled through the drain hole. They bought an extra drain plug and drilled a hole in it for their fill hose adapter.

 

[Pipino]

The valvomax is a smart litte device, but in this case not suitable to my opinion.
- It looks like the valvomax is made from stainless steel, not recommendable to use on aluminium surfaces like the BMW i3 gear box.
- it is missing the magnet for collecting any metal parts
- it seems too bulky to not interfere with the heat protection on the rex.

In May '23 I drained the gear oil and replaced the original plug (M16x1.5) with a galvanised plug with normal hex head (so can be tightened/loosened with spanner). A 0.8 mm hole was drilled through the plug and M5 standard thread with 90 degree angle to support a small hose tail and later a small modified cone point grub screw (hardness 12.9) to plug it off. A small but strong O-shaped magnet was attached to the new plug-end to catch any additional metal coming from the gear box. I used an aluminium washer and tightened it with a torque somewhat higher than the set value by BMW: the new aluminium washer had a larger total surface than the original one. Oil I used was 500 ml GL5 rated SAE 70W-80 from BMW via getbmwparts. This is the same amount I got out of the gear box. The oil went in under gravity (1 m), but it took some time (45 min - 1 h). After removing the hose tail NO oil came out, but nevertheless had everything prepared to inserted the cone grub screw with loctite threadlocker stick 37643 so I did it quickly.
Checked after 1 month and found no issues. Driving now for almost 10 months without problems and average mi/kWh went up. Can not prove it was due to the oil change, but logic says that it does help to get things running smoother.

I was thinking to make more of these modified plugs if there would be interest in them.

 

[nilknarf]

Great work! Best solution yet. Thank you for providing the size of the plug (M16x1.5). There are several online sellers that reference an M22x1.5 drain plug for the i3, with the BMW part number 33117525064, but I'm guessing that's incorrect. In fact I had just ordered an M22 fill adapter (VAS5162) last night and fortunately after reading this, I was able to cancel the order, so good timing with the post.

Edit: I just input my vin at realoem and found the part number for the drain plug. It's 11137720999 and it is indeed M16x1.5.

 

[Pipino]

Happy to help. But why did you order a new plug?

 

[nilknarf]

I didn't order a plug, I had just been researching the plug to determine the thread. I should have gone to realoem in the first place, but your post set me straight.

 

[dafireman12]

The valvomax is a smart litte device, but in this case not suitable to my opinion.
- It looks like the valvomax is made from stainless steel, not recommendable to use on aluminium surfaces like the BMW i3 gear box.
- it is missing the magnet for collecting any metal parts
- it seems too bulky to not interfere with the heat protection on the rex.

In May '23 I drained the gear oil and replaced the original plug (M16x1.5) with a galvanised plug with normal hex head (so can be tightened/loosened with spanner). A 0.8 mm hole was drilled through the plug and M5 standard thread with 90 degree angle to support a small hose tail and later a small modified cone point grub screw (hardness 12.9) to plug it off. A small but strong O-shaped magnet was attached to the new plug-end to catch any additional metal coming from the gear box. I used an aluminium washer and tightened it with a torque somewhat higher than the set value by BMW: the new aluminium washer had a larger total surface than the original one. Oil I used was 500 ml GL5 rated SAE 70W-80 from BMW via getbmwparts. This is the same amount I got out of the gear box. The oil went in under gravity (1 m), but it took some time (45 min - 1 h). After removing the hose tail NO oil came out, but nevertheless had everything prepared to inserted the cone grub screw with loctite threadlocker stick 37643 so I did it quickly.
Checked after 1 month and found no issues. Driving now for almost 10 months without problems and average mi/kWh went up. Can not prove it was due to the oil change, but logic says that it does help to get things running smoother.

I was thinking to make more of these modified plugs if there would be interest in them.

Definitely interested in ordering one!

 

[nilknarf]

I love Pinpino's solution and following his lead, I discovered that an M16 oil pressure sensor adapter will fit. The adapter accepts a 1/8" NPT male plug, so you can use a 1/8" NPT magnetic drain plug made for motorcycles. I also picked up a 1/8" thread to 3/8" barbed hose adapter to use as the fill adapter. The fill adapter swivels so that I don't have to worry about the stationary hose when I'm unscrewing the other end of the adapter.

Pipino's plug is still just as viable a solution and I believe that his drain plug is stronger than the oil pressure adapter. As he was still contemplating producing more, I thought I would post this as another option, but am hoping that he can ramp up production for the group.

 

[Chrism88]

I love Pinpino's solution and following his lead, I discovered that an M16 oil pressure sensor adapter will fit. The adapter accepts a 1/8" NPT male plug, so you can use a 1/8" NPT magnetic drain plug made for motorcycles. I also picked up a 1/8" thread to 3/8" barbed hose adapter to use as the fill adapter. The fill adapter swivels so that I don't have to worry about the stationary hose when I'm unscrewing the other end of the adapter.

Pipino's plug is still just as viable a solution and I believe that his drain plug is stronger than the oil pressure adapter. As he was still contemplating producing more, I thought I would post this as another option, but am hoping that he can ramp up production for the group.

Can you share the parts you used? Thanks

 

[Chrism88]

The valvomax is a smart litte device, but in this case not suitable to my opinion.
- It looks like the valvomax is made from stainless steel, not recommendable to use on aluminium surfaces like the BMW i3 gear box.
- it is missing the magnet for collecting any metal parts
- it seems too bulky to not interfere with the heat protection on the rex.

In May '23 I drained the gear oil and replaced the original plug (M16x1.5) with a galvanised plug with normal hex head (so can be tightened/loosened with spanner). A 0.8 mm hole was drilled through the plug and M5 standard thread with 90 degree angle to support a small hose tail and later a small modified cone point grub screw (hardness 12.9) to plug it off. A small but strong O-shaped magnet was attached to the new plug-end to catch any additional metal coming from the gear box. I used an aluminium washer and tightened it with a torque somewhat higher than the set value by BMW: the new aluminium washer had a larger total surface than the original one. Oil I used was 500 ml GL5 rated SAE 70W-80 from BMW via getbmwparts. This is the same amount I got out of the gear box. The oil went in under gravity (1 m), but it took some time (45 min - 1 h). After removing the hose tail NO oil came out, but nevertheless had everything prepared to inserted the cone grub screw with loctite threadlocker stick 37643 so I did it quickly.
Checked after 1 month and found no issues. Driving now for almost 10 months without problems and average mi/kWh went up. Can not prove it was due to the oil change, but logic says that it does help to get things running smoother.

I was thinking to make more of these modified plugs if there would be interest in them.

If you’re making these I’d love to buy one!

 

[Hirak4313]

Nilknarf- I would also be interested in the specific parts and the vendors you used. Thanks.

 

[nilknarf]

• Oil Pressure Sensor Adapter $10.99 at Amazon or $3.27 at Aliexpress There are also cheaper ones made of aluminum, but I went with stainless steel as I would be afraid of breaking an aluminum one when torquing. Stainless steel should be safe in this application as there is no electrolyte present to enable galvanic corrosion.​

• Oil drain plug: $9.99 + $5.00 shipping at Prism Motorcycles These can also be found for around the same price on eBay. Just search for 1/8 NPT magnetic plug or you can search the Harley Davidson part number of 739a.​

• Hose fitting: $10.99 at Amazon

 

[Chrism88]

• Oil Pressure Sensor Adapter $10.99 at Amazon or $3.27 at Aliexpress There are also cheaper ones made of aluminum, but I went with stainless steel as I would be afraid of breaking an aluminum one when torquing. Stainless steel should be safe in this application as there is no electrolyte present to enable galvanic corrosion.​

• Oil drain plug: $9.99 + $5.00 shipping at Prism Motorcycles These can also be found for around the same price on eBay. Just search for 1/8 NPT magnetic plug or you can search the Harley Davidson part number of 739a.​

• Hose fitting: $10.99 at Amazon

Thanks for sharing. So when you pumped it in did you just unscrew it quickly and pop in the drain plug? How did you keep the oil from spilling out?

 

[Pipino]

I found there were a couple of issues to be tackled:
- prevent oil spillage as much as possible : small hole 0.8 - 1.0 mm
- overcome the limited space because of heat shield : grub screw flush with head of plug
- keep magnet to collect any metal shavings: requires a strong magnet with a hole
- have the hole closed off properly (you don't want to have oil leaking from the gearbox after x amount of miles) : install a m5 hardened modified grub screw with 90 degree head in the plug which has the 90 degree counter form (used a special 90 degree drill to make this).

I can produce more of these plugs.
Can include the hose and tails to connect to the oil bottle cap, so you're all set except for the 500ml oil and loctite.

Send me a message if you're interested.

 

[Chrism88]

I found there were a couple of issues to be tackled:
- prevent oil spillage as much as possible : small hole 0.8 - 1.0 mm
- overcome the limited space because of heat shield : grub screw flush with head of plug
- keep magnet to collect any metal shavings: requires a strong magnet with a hole
- have the hole closed off properly (you don't want to have oil leaking from the gearbox after x amount of miles) : install a m5 hardened modified grub screw with 90 degree head in the plug which has the 90 degree counter form (used a special 90 degree drill to make this).

I can produce more of these plugs.
Can include the hose and tails to connect to the oil bottle cap, so you're all set except for the 500ml oil and loctite.

Send me a message if you're interested.

Sent you a message.

One other question: I assume you’re using some kind of pump to push the 500ml of liquid in. Is there a lot of loss there? Do you just add a few extra ml and call it good?

 

[Pipino]

Originally the set up included a 200ml syringe with a ~5 lb weight on it. But the seal in the syringe was not great and some oil bypassed it. It also did not go in much faster than under gravity (~4 ft).
I did get in all the oil in a very clean way.
Best set up that I can imagine now is: increase hole to 0.9mm or 1.0mm and connect the (1/4x1/8") hose directly to the cap of the oil container which is placed upside down on a high level, say 4-5 ft above gear box. make a pinhole in the bottom of the container to allow air in.