Manual Gearbox Oil Change

The gearbox is apparently a sealed for life item.

Renault say the gearbox oil doesn't need changing during the service life of the car, I say different.

The gearbox oil is subjected to much higher loads than those imposed to engine oil. That's why box oil is called EP (extreme pressure).

So what oil should you use? The recommended oil by Renault is Tranself TRX 80W, although any EP gear oil thats 80/90 is fine. You can also use automatic gearbox oil. There are some fancy gearbox synthetic oils out there and these can also be used but I'm tight so I tend to use mineral and change it more often.

Engine oil although not recomended can be used in an emergency, by emergency I mean box is nearly emtpy, miles from home, and you have a tin of it you can pour it in. When you get home change it ASAP. I ran a JB1 'box for nearly 20k miles on ASDA 3 quid engine oil, it still works fine. I eventually put the right oil in it when the synchros started to cease working, although they worked fine with the right oil, but I don't suggest you try this.

To purchase gear box oil I suggest a motor factors, places like halfords will charge you around £7-£8 for a one litre bottle, whereas a motor factor will sell you 5 litres for about £8. I use Comma stuff as its cheap, good and it comes in 5L bottles.

Capacities, well these range from 2.75 litres up to 3.5 litres. If you have a gallon tub then you have no problem, if you buy 1L bottles then I'd get 4. This way if you have a full bottle spare you can take it back, the boxes never drain fully by the way.

The tools you need:

Fingers
Fresh EP Gearbox Oil
Copper Washer*
13mm Socket or Sump Plug Socket

*I recommend buying a new copper washer, although if re-used they don't tend to leak. It's the same size as the engine sump plug washer.

Righty let's go!

This picture is of the underside of the car. The black plastic cover you can see between the subframe and the exhaust is hiding things.....



On early cars this cover is held on with a 16mm bolt. On some cars it's missing and on some cars its merely clipped over an existing gearbox bolt. This is it removed, its usually full of oil and debris, so clean it.



I know it's dark but here I am pointing to the actual drain plug, the silver rod to the front of the car is the gearbox selector arm, this is where oil seeps out.



this is the actual drain plug and the washer, this is what you look for. Notice the sensible design, both a square hole and a 13mm hex on it.



This is the oil draining, this will take some time. It helps if you remove the filler plug and the breather box/stub.



This is the oil, you may find it has a silver tinge to it, this is swarf ground off in the 'box due to it breaking in and general wear and tear. It's not meant to be black. You may also find there's a lot of water in the oil if the car isn't used on long-ish journeys.



Now the oil has drained out you can refit the plug along with its new washer, if you're not re-using the old one. Here's the oil I used for that change, got it cheap!



Now you need to fill it, where do I fill it you say, here I say!



This is a combined filler/level plug. Now apparently on some boxes the plug has a small dipstick on it, well I have yet to see one on any Renault. So to make the box at the right level you fill it up to the plug hole.



With the bottles in the pic its easy as you squeeze it in. For the big bottles what i use is a 3 foot hose with a funnel in it. You can also cut the top off a 2L Coca Cola bottle and use that as a funnel. Pour it down the hose.

When it's full, take it a drive using all the gears. Leave it to cool and re-check the oil level - top up if required.

The main problem with the filler plug is access, on some cars you will need to completely remove the airbox assembly to get better access but I suggest you do it.

Changing the oil will ensure smoother changes, longer gear box life and also will help to keep transmission losses low.