Maintenance – Suzuki Jimny JB74 Drivetrain Oil Changes

Having recently hit 12,500 miles it is time for the drivetrain to receive a fresh dose of oil! If you’re keen to know how to change all the oils on your Suzuki Jimny drivetrain then look no further.

First things first! Quick Disclaimer! We are not trained mechanics. What we do is our decision based upon a lot of research and plenty of trial and error. What you do is your own decision that you will make yourself. We will not be responsible for your actions.

In this write up we will show you how we changed our oils in the drivetrain. The drivetrain consists of a Gearbox, Transfer Case and two Differentials. Our Jimny is a manual so sadly for the automatic owners you will need to look up how to change the oil in your automatic gearboxes somewhere else. Please refer to your handbook to make sure you have obtained the right amount of fluids for this job. To save you time, here is a photo out of our handbook.

Suzuki Jimny JB74 Gearbox Transfer Case Differential Oil Amount
Page 9-8 in the Official Suzuki Jimny 2018+ Handbook

So let’s talk quickly about oils! After a lot of research and headaches we learnt that you shouldn’t use the same oils in a manual gearbox as you would in a differential! Differentials have a set of gears called ‘hypoid gears’ which during heavy use can see a lot of pressure on their ‘teeth’. Due to the higher pressure on the ‘teeth’, differentials will use a type of oil which falls under the GL-5 specification. This GL-5 oil is not very healthy for a manual gearbox. In a manual gearbox you will find Phosphorus Bronze bushes between gears which helps align each gear to allow for a smoother shift between gear changes. GL-5 oil can speed up the wear of these bushes which will shorten the life span of your gearbox. This is why you should be using GL-4 specification oil when a gearbox contains Phosphorus Bronze. With that out of the way, the oils we have chosen to go with are photographed below:

Here are the tools you will need:
10mm Square Drive Key (for the fill and drain plugs)
– 17mm Spanner (to hold the 10mm Square Drive Key in awkward places)
– Ratchet
– 17mm Socket (to hold the 10mm Square Drive Key)
– Wire Brush

You will also need a way to refill the drivetrain with oil. Here are two popular items you can use. The item on the left is an ‘Oil Syringe‘ which has been used in the past however it constantly caused a mess every time we used it. For this Jimny we treated it to a new ‘Oil Pump‘, the item on the right. This style of pump is far easier to use and a lot easier to handle so we would highly recommend you get one similar to the one on the right.

Make sure you also have a container to catch the old oil.

Before we begin changing any fluids there is one thing that needs to be mentioned. When you come across an enclosure that contains oil, you will usually always find the drain plug at the lowest point of the enclosure to ensure as much of the old oil is drained. The fill plug will usually be found somewhere on the side of the enclosure. The reason it will be somewhere random on the side is to make sure you don’t over fill the enclosure. As your filling up with oil and you notice it is coming back out, then this is a good sign to stop filling as you have reached the required amount.

It is very important to always keep the enclosure, in this case the Jimny, as level as possible otherwise the fill level might be altered if the enclosure isn’t level giving you an incorrect amount of oil.

Another important fact to remember about fill and drain plugs is to always make sure you’re able to remove the fill plug before removing the drain plug otherwise you will be stuck if you have drained all your oil but then unable to refill it.

Differentials

So let us begin with changing the front and rear differential oil. In this instance we did the rear one first which is what we will show you the procedure on. The front is the exact same procedure however it requires a little more oil.

Locate your plugs that you will need to remove and give them a little scrub with a wire brush and then wipe with a cloth to make sure no dirt gets inside the ports.

Rear differential

Using the 17mm socket attached to a ratchet, remove the drain plug and allow the old oil to drain into an old container. (remember to loosen the fill plug!)

Allow as much as possible to drain.

Whilst waiting for the oil to drain, give the plugs a good clean. The drain plugs are usually magnetic to attract metal particles when the oil settles to prevent the metal particles from recirculating.

Once all the oil had drained, refit the drain plug and start refilling the differential with fresh oil. Once you notice oil coming back out, stop refilling and refit the fill plug.

Once you’re happy that both plugs are back in, give the area a little clean.

Seeing as you have now completed the rear differential you can easily go repeat these exact same steps for the front differential. Bare in mind that the front requires a little more oil.

Transfer Case

Now drag yourself under the Jimny and locate the Transfer Case fill and drain plugs. Again give the surrounding area a little clean. You can’t see it in the photo as we moved it out the way, but there is a cable clipped to the bracket between the plugs, we found it easier to move the cable out the way and tucked it behind the driveshaft.

Following the same procedure like before, remove the drain plug to drain all the old oil but make sure you have loosened the fill plug to allow the oil to flow more steadily as this drain plug is on the side.

Whilst waiting on the oil to drain, make sure to inspect the drain plug and give it a good clean. As you will see in the photo below our plug has collected quite a bit of metal particles. This is exactly why maintenance is important.

Ahhhh! Much better! That’s how the plug should look! When your happy with how clean your plug looks, refit it and start refilling the transfer case with fresh oil.

Refill the transfer case back up with fresh oil, once again when you see it starting to come back out then stop refilling and refit the fill plug.

If you did move the cable out of the way, then refit it!! You don’t want it ripped off by your driveshaft! Also make sure to clean up any excess oil.

Now that you have finished refilling with GL-5 oil, make sure to empty the oil out of the pump and let it drain for a while. Refill the oil pump with fresh GL-4 oil ready for the gearbox.

Manual Gearbox

Now drag yourself even further under the Jimny to access the awkward fill plug on the side of the gearbox. Once you have located both, again give them a little clean so you can repeat the same procedure for the fourth time.

Whilst you once again wait for the oil to drain, inspect the drain plug and you’ll probably notice that there will be metal particles on this plug too! Especially if you have crunched your gears a few times when changing gear. Clean the plugs as usual and refill the gearbox back up with fresh GL-4 oil.

As you can see in this photo this little oil pump is a charm. With the hose being long enough and having a little hook shape metal pipe on the end, you can hook the pipe into the gearbox and begin pumping fresh oil back in. As always remember when you see oil coming out the fill plug you have reached the required amount.

Finished!

Now that you have finished, give everything a good clean, oily tools and equipment is just a pain in the back side. Make sure to pour away the old oil in a safe manner. It is always a good idea to visit your local recycling centre and dispose of the oil there rather than down your drain! Save the planet!

As you pour away the oil into a bottle, you may notice very fine metal swirling around in the oil mixture, this is a good reminder that maintenance is key. Look after your investment and it’ll look after you!

Thank you for reading and we hope this helps you in the future!

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