Change the Gearbox Oil

* The pictures are from an oil change conducted on an ST205, but the location and method remains the same for all GT4 models *

When should I change my gearbox oil?

The level should be inspected every 15,000 and changed every 30,000 miles.

How much oil do I need?

The specification is 5.2 litres of oil, however, I used just a smidge short of 5 litres, (on the 205), and that was after a thorough draining of oil from the gearbox and transfer case.

The listed gearbox oil specification is 75W/90 or 80W/90 grade API GL5.

Are there different types of gearbox?

Yes, and it depends upon which model of GT4 you own:

What tools do I need?

• 10mm & 24mm sockets and spanners
• Torque wrench
• Lots of rags
• Large bucket to catch all the old oil
• 50cm Length of 1.5cm, (maximum), outer diameter pipe with a funnel

Aren't there a "few" types of gearbox? Am I going to get it right!?!

There are a "number" of gearboxes on the GT4, but it's probably easier to think of one on it's own at the rear of the car, and a few stuck together in one lump at the front of the car bolted onto the side of the engine.

In summary:

Front - transmission, centre differential, front differential and transfer assembly.
Rear - rear differential

The front gearbox utilises the same oil that flows throughout the entire gearbox, so no individual point requires to be accurately topped up, but instead the level for the whole gearbox is set i.e. just fill it up!

How do I fill up the gearbox?

The easiest way that I have found is via a length of pipe with a funnel attached to it and pushed into the gearbox filler hole. An alternative method is to remove either the breather plug or lock bolt (24mm) located on top of the gearbox. I have been reliably informed that the 24mm lock bolt can be removed with any ill effect. Personally I though it was a bit of a pain to get to and I didn't want to risk any chance of either debris entering the gearbox or removing a part that was a crucial part to the gearbox that I didn't feel happy with "simply removing" without knowing it's consequence...

Anything else I need to know?

Best done on a ramp or you might get covered in oil! Make sure that you can undo the filler nut before you drain out the old oil...

All three of the drain/filler plugs should have a new seal fitted...

The torque settings are as follows (Nm):

Okay. How do I do it?

	Take the car out and warm the engine through until it is at operating temperature, to ensure that the gearbox oil is up to operating temperature
	Jack the car up and ensure that the car is level. Remove enough bolts from the lower front right under engine bay plastic tray, and hinge this down and out of the way to obtain access to the gearbox, approx 6 bolts/screws
	Undo and remove the gearbox filler plug located half way up on the front on the gearbox, opposite the radiator
	Locate one of the drain points, and remove the drain plug. I suggest the transfer case first as this will create less mess. The plugs require a 24mm socket. Have your bucket handy...
	Once the transfer case has drained, replace the drain plug and torque to 39Nm. Next, remove the gearbox drain plug, drain the oil and then replace, torque to 49Nm. Access to this plug is tight and you will not be able to torque this will a conventional torque wrench
	Locate the filler plug hole and insert your very clean plastic tube into the filler hole after feeding the tube down through the engine bay by the radiator, and begin filling from above the engine bay. I would suggest filling with all the 5 litres from your 5 litre can...
	Once filled remove the pipe and let the small amount of excess oil drain out from the gearbox. The correct oil level is when the oil is at the bottom of the filler plug hole. Refit and torque the filler plug to 49Nm

Any questions or comments then please feel free to e-mail me

Other jobs to do at the same time?

• Change/inspect the gearbox oil cooler supply/return pipes - they are prone to rusting through - picture
• Change the engine oil

Any other points of interest?

Some owners have filled their gearbox with ATF to reduce friction losses associated with the gearbox and improve wheel output power. Click here to read my ATF article.

The first time I changed the gearbox oil it took me 2 hours, but I was poking about a lot and inspecting other things. If I had this guide it would've taken easily <1 hour.

Top of page