[i30bluedrive]

Hi all,

I'm looking to get gearbox oil changed on my 2014 1.6crdi.

My understanding is that the correct spec for the gearbox is 75W85 GL4. I am looking to get some Redline MT85 which I have heard is good stuff. In the manual the capacity is stated as around 1.8-1.9l - can anyone who has changed this confirm this - the Redline comes in 946ml bottles so my plan is 2 should be enough.

[BrendanP]

I'm in the UK, I've changed the gearbox oil on my 2011 FD diesel a couple of times, and will shortly be doing it on my 2015 GD diesel. I think the gearboxes are  pretty similar. I used Comma SX 75W85 GL4 oil which comes in litre bottles, and two was enough. I don't know what country you're in and what brands are available, but Comma was the exact spec. Some brands claim they are suitable for GL4 and GL5, but I'm not so sure. The older car has done 296,000 miles with no gearboxes issues, and that's with a 90,000 mile interval. The GD is every 60,000 miles.

I've just looked on the Comma website and they don't show it anymore, only 75W90 in GL4 or GL5. Maybe I'll try and find someone with old stock.

[I30 GD]

I've refilled with Comma 75w90 gl4 fully synthetic, took just under 2 litres, spoke to my mechanic, he said 75w90 is fine as a substitute

[i30bluedrive]

I'm in the UK, I've changed the gearbox oil on my 2011 FD diesel a couple of times, and will shortly be doing it on my 2015 GD diesel. I think the gearboxes are  pretty similar. I used Comma SX 75W85 GL4 oil which comes in litre bottles, and two was enough. I don't know what country you're in and what brands are available, but Comma was the exact spec. Some brands claim they are suitable for GL4 and GL5, but I'm not so sure. The older car has done 296,000 miles with no gearboxes issues, and that's with a 90,000 mile interval. The GD is every 60,000 miles.

I've just looked on the Comma website and they don't show it anymore, only 75W90 in GL4 or GL5. Maybe I'll try and find someone with old stock.

Thanks Brendan, I'm UK based too. The stuff I'm looking at is quite expensive,  £26 for 946ml, so I'm hoping 2 of these should suffice. https://www.opieoils.co.uk/p-74033-red-line-high-performance-synthetic-mt-85-75w85-gl-4-gear-oil.aspx?variantid=97568

My car is at nearly 88k and as far as I'm aware, it hasn't been changed. Some gears are a bit notchy now so I thought it was a good time to go ahead and get it done. There certainly doesn't seem to be an abundance of 75W85 GL4 oils on the market.

[i30bluedrive]

I've refilled with Comma 75w90 gl4 fully synthetic, took just under 2 litres, spoke to my mechanic, he said 75w90 is fine as a substitute

Thats good to know - at what mileage did you change yours and did you notice a marked improvement after ?

[I30 GD]

I changed it to try and solve intermittent gear changing problems at about 100k miles, it helped but the problem was the clutch/hydraulics.

[BrendanP]

There is an oil for Vauxhalls, GM part 93165290 for a 1 litre bottle, which appears to be the correct spec. A friend bought some the local Vauxhall dealer and it was about £25 for 2 litres. A lot of traders on ebay also describe it as 75W90, but it doesn't say on the label.

[BrendanP]

I was wrong about the gearbox oil I used. I found the bottle in the garage and it was the SX 75W90 GL4, which is a semi-synthetic. On the Comma website it now recommends the fully synthetic oil for the 2011 car, and for the 2015 car, it doesn't have a recommendation at all.. My friend told he paid £3 for a litre bottle of the Vauxhall oil, which is a fully synthetic, so I might nip in tomorrow and see if they still have on the shelf.

[Pieman]

Is this an easy job?  I sometimes have trouble changing gear.  Intermittent though.  Changing oil won't hurt. Car is on 125,000 miles. Thanks

[BrendanP]

I've changed it on an FD, I think the gearbox is similar to GD. Just make sure you know where the drain and fill plugs are. Fortunately, I have a sloping drive so I was able to drive the front wheels onto ramps to get the car level and be able to get underneath it. Make sure you can loosen off the fill plug BEFORE taking out the drain plug and letting all the old oil out. Put the drain plug back in after the oil has stopped dripping out.

The new oil bottle usually comes with a short filling spout but there's not much room to manoeuvre the bottle into position, so what I do is sling a plastic funnel from the bonnet lid, and push some plastic tubing over the end, then poke the other end into the filling hole. Pour the new oil into the funnel and let it run into the gearbox until it starts to ooze out of the filling hole. pull the hose out of the filling hole and into the new oil bottle to capture the oil in the funnel and the tube. Refit the filling hole plug. According to the service schedule I have it should be changed every 60,000 miles.

[Pieman]

I've changed it on an FD, I think the gearbox is similar to GD. Just make sure you know where the drain and fill plugs are. Fortunately, I have a sloping drive so I was able to drive the front wheels onto ramps to get the car level and be able to get underneath it. Make sure you can loosen off the fill plug BEFORE taking out the drain plug and letting all the old oil out. Put the drain plug back in after the oil has stopped dripping out.

The new oil bottle usually comes with a short filling spout but there's not much room to manoeuvre the bottle into position, so what I do is sling a plastic funnel from the bonnet lid, and push some plastic tubing over the end, then poke the other end into the filling hole. Pour the new oil into the funnel and let it run into the gearbox until it starts to ooze out of the filling hole. pull the hose out of the filling hole and into the new oil bottle to capture the oil in the funnel and the tube. Refit the filling hole plug. According to the service schedule I have it should be changed every 60,000 miles.

Thanks. I will look into it.  Long overdue.