This question has come up a few times since I've joined this forum only a short while ago. To act as a better resource i've made this as a standalone thread. Here are all the details needed for the transmission component oil changes. Mine is the 2.0 TDCI 2018 MK2 kuga, but will apply to many others using the 6 speed manual gearbox. None of it is difficult, and all can be done on the driveway with just a few simple tools. Only the rear diff requires a very easy to modify tool which can be bought in screwfix for under £5. The overall cost to change all these fluids is not much at about £45 at the time of writing.
For all of these you will need a way to fill them with oil, and for the rear diff you will need a way to suck out the oil. I reccomend either a small oil pump, or an oil syringe such as this. You also 'should' replace the plugs but I just cleaned mine up and put them back in, sometimes I use a bit of PTFE tape if it's something like this which I won't now touch for another 50k miles or so.
There are 3 transmission components which can have the oil changed: the Gearbox, the PTU, and the rear differential:
The gearbox and PTU are accessible from the front of the car on axle stands from the front of the car, you just need to remove the black plastic undertray.
The rear differential is accesible under the rear of the car, you don't actually need to jack the rear of the car up to access it but of course it makes it easier. There is a black plastic undertray held in place by two bolts which needs to be removed, then you have access to the rear diff.
I hope this is helpful for people who are intending to do this job on their cars.
MMT6 Gearbox
These are the gearbox plug locations (1 is drain plug, 2 is fill plug).
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Power Transfer Unit
This is the PTU fill plug location in the diagram. The diagram I have only shows a fill plug, but mine actually had a drain plug too on the bottom (Photo underneath: fill plug blue arrow, drain plug pink arrow).
![Image]()
![Image]()
Rear Differential
As there is no drain plug, you have to suck out the oil ideally using a flexible silicone tube i.e fuel line and a syringe/oil pump. The rear diff fill plug location is shown in the diagram below. It is a 1/2" square as I described in my previous post. You need a radiator key cut down to 20mm long at the square end as pictured below. You need the square end to go in the plug, and then use a spanner on the 13mm hex end to undo it. The length of your cut-down key is very important as you don't want it to be too long and get stuck against the cross member as you back it out. This is hard to appreciate without seeing the thing in situ but when you get under the car and see where it is it is obvious. I would also highly reccomend only using the open end of a normal spanner, definitely DO NOT use a ratchet spanner as if you start backing it out and get too far, it will be stuck with no return!
![Image]()
![Image]()
For all of these you will need a way to fill them with oil, and for the rear diff you will need a way to suck out the oil. I reccomend either a small oil pump, or an oil syringe such as this. You also 'should' replace the plugs but I just cleaned mine up and put them back in, sometimes I use a bit of PTFE tape if it's something like this which I won't now touch for another 50k miles or so.
There are 3 transmission components which can have the oil changed: the Gearbox, the PTU, and the rear differential:
The gearbox and PTU are accessible from the front of the car on axle stands from the front of the car, you just need to remove the black plastic undertray.
The rear differential is accesible under the rear of the car, you don't actually need to jack the rear of the car up to access it but of course it makes it easier. There is a black plastic undertray held in place by two bolts which needs to be removed, then you have access to the rear diff.
I hope this is helpful for people who are intending to do this job on their cars.
MMT6 Gearbox
These are the gearbox plug locations (1 is drain plug, 2 is fill plug).
- Spec is 1.89l of WSS-M2C200-D2.
- I used Comma MVMTF Plus 75W FS Manual Gear Oil which meets the above spec. Mine took the full 2L I had purchased without starting to spill out the fill plug. I've left mine with that though.
- Tourque specifications are 35nM for both plugs. Mine were Hex although some people report having Torx plugs.
Power Transfer Unit
This is the PTU fill plug location in the diagram. The diagram I have only shows a fill plug, but mine actually had a drain plug too on the bottom (Photo underneath: fill plug blue arrow, drain plug pink arrow).
- Spec is 0.8L of WSL-M2C192-A.
- I used Castrol Transmax Limited Slip LL 75W-140 which meets the above spec.
- Tourque specifications are 34nM for the Torx T50 fill plug.
Rear Differential
As there is no drain plug, you have to suck out the oil ideally using a flexible silicone tube i.e fuel line and a syringe/oil pump. The rear diff fill plug location is shown in the diagram below. It is a 1/2" square as I described in my previous post. You need a radiator key cut down to 20mm long at the square end as pictured below. You need the square end to go in the plug, and then use a spanner on the 13mm hex end to undo it. The length of your cut-down key is very important as you don't want it to be too long and get stuck against the cross member as you back it out. This is hard to appreciate without seeing the thing in situ but when you get under the car and see where it is it is obvious. I would also highly reccomend only using the open end of a normal spanner, definitely DO NOT use a ratchet spanner as if you start backing it out and get too far, it will be stuck with no return!
- Spec is ?0.6L of WSP-M2C197-A (That quantity is from another forum post on here, I don't have it in the manual. I took about 0.3-0.4L out of mine when draining it but put the 0.6L back in)
- I used Castrol Transmax Axle Long Life 75W-90 which is a synthetic oil.
- The spec is for a cheaper mineral oil (This) which would be another option.
- Tourque specifications are 20nM + 180 degrees for the 1/2" square fill plug.
