GUIDE : Changing your gearbox fluid

An often-neglected fluid is the transmission oil yet damage due to insufficient lubrication can be severe. Due to a slight oversight by VW, the hole used for checking the fluid level is in the wrong place on the older gearboxes which means that you can't easily tell how much oil is in the box itself.

On the older cars you can remove the fill plug (which is the one used to check the level) and see if fluid comes out but this will only tell you that there is over 1.5 litres present and there should be 2.0 litres. My recommendation is that every couple of years you fully drain down and refill the box as shown in this guide.

Note for the later gearboxes (post September 8th 1987) the fill hole was moved up (7mm I believe) which means it is suitable for checking fluid levels properly.


Step 1 - Jack the car up (prior to doing this loosen the wheel nuts on the front passenger side wheel). Don't forget to use axle stands.



Step 2 - Remove the nearside front wheel completely now which gives you access to the refill hole (highlighted) and the rest of the gearbox



Step 3 - I read a lot about people getting 17mm allen keys, whilst this is a feasible method of removing the drain plug, my preference is to be able to use a socket. Thankfully I already had the ideal tool for the job which is shown in this picture, it is designed for certain sump plugs and is readily available from any good motor factor. It is 17mm on one side and 14mm on the other allowing you to effectively put a 14mm socket onto the drain plug.

Step 4 - Locate the main drain plug for the transmission which is another 17mm plug like the one shown previously



Step 5 - Using the tool described in step 3, fit it into the 17mm recess used for draining the transmission oil



Step 6 - One of the benefits of using a socket is that you can get a 3 foot breaker bar on in case the sump nut is seized solid like mine was!

Step 7 - Place a suitable oil pan underneath the drain plug and remove it by hand (just like a normal oil change, try to prevent the plug from falling into the oil).

Note: Transmission oil smells - a lot. It is one of the most pungent fluids you'll find on a car and scrap yards stink of the stuff. Wear throwaway clothes and try and avoid getting it everywhere, use a container that can hold at least 2 litres of the stuff (should you have the correct amount in your gearbox by some stroke of luck!)



Step 8 - Leave the box to drain completely, there should be virtually no oil dripping out by the time it is empty (this is a shot of mine just after removing the plug, there wasn't much oil in it at all!). Second picture shows how much I got out, this is a 5 litre container … almost empty!

Step 9 - Locate the code on the bottom of the bell housing (the big metal piece around the gearbox). Use a bit of gear oil or petrol etc to wipe the tag clean and read the date code. 08097 boxes have the repositioned inspection hole, for older cars (like mine) it is somewhat less than useful. My code's last 5 digits are 05043 because it is a 1983 car so I know the hole is in the wrong place.

For both old and 'new' boxes you COULD fill through the speedometer hole. For the post-1987 box I'd just use the fill hole shown in step 2 but because that was not possible for my car I've simply filled the whole box through the speedo (some people recommend filling using the normal fill hole then adding the final 1/2 litre through the speedo for some reason).

On all '020' Golf gear boxes 2.0 litres of fluid will be required



Step 10 - Clean up the drain plug, the threads will probably be covered in dirt from exposure to the road so give it a good scrub with some petrol and a rag to prevent any dirt from the threads entering the system

Step 11 - The first picture is to give you an indication of where in the engine we are looking. The second picture shows you a view looking down through the engine towards the top of the gearbox. It's a little unclear from the picture but you should be able to follow a sleeved cable down to the box itself (this is the speedometer cable), it terminates in the box itself. There is a 10mm bolt which holds the metal speedometer cable flange into the gearbox itself

Step 12 - I found the easiest way to undo the bolt was actually from above the engine looking down on the box, you'll need a lot of extension bars though! See pictures for how I did it but you can also get to it from underneath with the wheel removed - you'll have to do this by feel because you can't quite see the bolt with your spanner/socket in place

Step 13 - Once you've removed the 10mm bolt from the flange, you should be able to rotate it and gradually ease it up out of the gearbox. Be careful when removing this that you do not damage the seal (picture 1). Then simply pull the speedometer drive gear out of the gearbox (try not to stress the cable too much here, grip in two places and rotate the cable as you pull it to free the unit from the transmission housing). The second picture shows the speedo gear removed (the orange plastic bit)

Step 14 - From underneath, slide a funnel into place so that it sits in the hole for the speedometer. The picture is a little unclear so I've circled the funnel



Step 15 - Use a length of hose (garden hose if you can do no better but preferably something a bit wider to prevent air getting trapped) to give yourself good access to the funnel without using contorted methods from underneath. You could do this the other way round and have the hose in the box and the funnel at the top but either way use hose and a funnel to make life easy



Step 16 - I poured a small amount of fresh transmission oil through before I put the 17mm drain plug back in so I could see how long it took to travel through the box. The answer was about 10 seconds so if using the fill hole, allow at least 15 seconds for whatever you pour in to come out.

Refit the 17mm drain plug and tighten

Step 18 - Once you've slowly filled your box with 2 litres, remove your custom filling tool!



Step 19 - Now simply replace the speedometer drive gear and the flange then tighten the 10mm bolt



Have a quick check round for any signs of leaks, wipe away any spilt oil then fire the car up. Give it a minute checking for drips from the drain plugs then go for a test drive

NOTE: You might want to put the wheel back on before the test drive

Forgetful today - the other two things I meant to say are:

1. Don't pour the gear oil into the hole that you can see next to the engine (with a rubber boot or sensor on it). This is an inspection hole so that lets you set your timing and putting fluid in here will destroy clutches, make sure you only use the fill hole shown or the speedo

2. The redline MTL can apparently sometimes help with crunching between 1st and 2nd gear

I'd use the correct filler hole with car passenger side jacked up so that it takes the full 2 litres.

Never had it happen to me but lots of speedo drive cogs have disappeared inside the gear box when trying to be removed. Disturb at your peril.

Otherwise 10/10 !

Interesting, hadn't heard about that when I did the guide otherwise would've considered it. I should imagine the speedos are due to brute force - if you rotate them out of the gearing then there shouldn't be much of a problem as far as I can see unless it's a weak component?

Only tip I can add is

"ENSURE YOU CAN FILL IT BEFORE YOU REMOVE THE DRAIN PLUG"

If the speedo cannot be removed for whatever reason or the filler plug cannot be accessed and undone then dont drain it or you`ll have an empty gearbox and no way of filling it  :wink: