This doesn't have to be a regular check but pays to check it every now and then... or if you suspect you have a gear oil leak..
Also oil is a known pollutant and a criminal offence to dispose of oil down the drain it must be disposed of safely and legally
For your nearest disposal point) look here: http://www.oilbankline.org.uk/
Or call 08708 506 506
so first park the car in a safe traffic free area WITH THE CAR AS LEVEL AS POSSIBLE
12mm hex (alan key or a 12mm hex socket and ratchet)
funnel with flexi end
bit of rag
if fussy a pair of latex or similar gloves
correct gear oil (see owners handbook)
SAE 75W-85 grade synthetic base lubricant.
FIAT 9.55550-MX3 certification
Reference N° F010.B05
apply the handbrake
the 12mm hex bung is a taper fit and is the level check and top up point
(there is another 12mm drain plug at the lower back of the gear box near the differential to drain all the oil should you wish to do a full change (capacity is 1.5kg of fluid according to the handbook)
If your car comes with a undertray remove this now your looking on the passenger side (uk) of the car for this
remove the 12mm hex bung with a alan key or ratchet with 12mm hex socket
now if you remove the bung you should get a dribble of oil escaping
if this happens your level is fine and just needs the bung cleaning with a bit or rag and nipping back up however if none escapes you need a top up
At this point stick your little finger in the hole angled downwards this should give you an idea of how much oil there is in the box if you cant get any oil on your finger you have a bad leak and should investigate where the oil is escaping to/ from as not only is this a sign of a problem it can also be dangerous to other road users if your car is loosing oil all over the road...
once any leak had been found/ delt with its time to top up with your flexi funnel in place....
fill slowly then when oil starts escaping from the filler then stop filling remove the funnel and allow any excess to drain away into your drip pan....
next clean up the top up plug and screw back in hand tight before nipping up with the alan key ( torque to 2.3 to 2.8 DaNm)
then wipe clean any drips (and refit under tray if fitted)
(see a nice easy task that can save you a lot of money and heartache)