Author Topic: GUIDE: how to change gearbox oil.  (Read 473 times)

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GUIDE: how to change gearbox oil.
« on: February 17, 2018, 07:36:26 PM »
Changing the oil on any gearbox can be tricky. It’s usually the filling up part that tends to be the stumbling block as they never really have a filler cap like engines do. This has a lot to do with the fact that it shouldn’t really need changing that often (if at all) but the 126 gearbox is a leaky one and an oil change helps prelong the life and keep those gear changes nice and smooth :D it’s actually quite easy if you use some ingenuity and can easily be done in half an hour. This guide is on a BIS but can in most cases be applied to the air cooled one too.

To make life easy it’s best to get the back end in the air about 6-8 inches

Once you’ve scrambled underneath look towards the starter motor and you will see a square nut sticking out the side of the gearbox. This is the filling point. I find it best to remove this FIRST as the last thing you want is to drain the old oil out and find you can’t fill it back up. It’s a funny size so I found a 1/2 socket end to be the perfect size so tap it on and use a 15mm socket on the other end. Here it is removed.

With the filler plug out and making sure you have a Suitable oil container you can now undo the drain plug. It’s a standard Allen key so no drama there. It may be tight.once out let it drip for a bit.

Once all the oil is out refit the drain plug. Now it’s time to refill. If you can, use a length of petrol hose - about 10mm wide - and push it in the filler hole. Push the other end up past the stater motor, then fit the biggest funnel you can in the other end. Because I have a BIS I tied the funnel to one of the engine lid levers. The oil choice is up to you but I used 20w50 mineral oil and it takes 1.1 litres.

With this done pull the hose out then refit the filler plug. Job done :D

« Last Edit: February 18, 2018, 06:56:52 PM by Gadge »

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