Gearbox Oil Change

After refurbishing the Gear Lever and Linkage I thought i’d change the gearbox oil as I doubt it has been changed since 1991.

Just like the other jobs i’ve completed I simply crawled under the van to do this, it’s a tight squeeze but manageable.

Shopping list:

• Comma 80W90 GL-4 Gear Oil 5L (make sure it is GL-4)
• Oil Drain Pan 6L (this one is rubbish, don’t buy)
• Draper Oil Funnel with Tube
• Gearbox Oil Filler Plug
• Gearbox Oil Magnetic Drain Plug
• Gearbox Fill/Drain Plug Key – 14/17mm

The Drain and Filler plugs are not essential but I wanted to replace with new as the current ones looked corroded and I could damage them during removal.

Funnel, Drain Pan, Gear Oil, Plugs and Key

Magnetic Drain Plug, Filler Plug and 14mm/17mm Key

Before you start, go for a nice drive somewhere to warm up the gearbox as the oil will flow better and make draining easier.

First thing is to remove the Filler Plug, this is the one on the side of the gearbox next to the selector shaft.

Filler Plug

I used the Gearbox Key with a 14mm spanner to remove the Filler Plug. There is enough room to whack the spanner with a rubber hammer to get it out, mine was quite stiff so I gave it a good squirt of Plus Gas Releasing Fluid first.

It important to remove the Filler Plug before the Drain Plug. The Filler Plug may have seized and be impossible to remove, if this is the case you will have no way of refilling the oil if you have drained the gearbox. Follow this handy flowchart:

Drain Plug

The Drain Plug is located underneath the gearbox to the rear.

Gearbox Drain Plug Position

Gearbox Drain Plug Position

Mine had quite a bit of corrosion so I cleaned out the inside to ensure the Gearbox Key went all the way in. Position the drain pan underneath and unscrew.

A word of warning: Gearbox oil STINKS. The drain pan I used could not deal with the initial flow of oil so spilled over the side onto the floor and onto me.

Draining Gearbox Oil

Oil Drain Pan

The Drain Plug is magnetic to collect any bits of metal floating around in the gearbox and protect your gears in the process. Here is Sir Adventure’s drain plug showing 25 years of gear wear:

Once the oil has finished draining you can replace your cleaned Drain Plug or like me, fit a new one. The plug does not go all the way in, there is some thread still visible when tightened.

Refilling

I used a Draper Oil Funnel with Tube and it was the perfect length to pour the new oil in from the engine bay. The pack also includes a handy screw on funnel for the 5L bottle.

Tube from engine bay over the top of the gearbox

Tube going around the gear selector

Tube into the filler hole

The gearbox takes 3.5L of oil, I poured 1.5L into a separate container then slowly poured the rest into the funnel. Once oil starts to pour out of the filler hole (if the van is level) the gearbox is full. Remove the tube and refit the Filler Plug. Job done!