Most people ignore transmission fluids. Even worse most people only talk about the importance of flushing an automatic transmission. If you have a manual transmission automobile, don't neglect that gearbox. Old oil can have metal shavings in it as well as sludge build up. Just as with motor oil, and oil change is cheap insurance. This instructable I'll show you just how simple this process is.

Step 1: Gather Your Tools.

Gather the tools and materials you will need for this job.

You will need:

- Jack and Axle stands or tire ramps to get your car off the ground
- Set of wrenches and ratchet set (depending on your vehicle.)
- Torque wrench
- oil drain bucket of some type
- Fluid pump
- rags
- WD - 40 or a penetrating oil
- Gear oil (most likely 75-90 or 80-90, check your owners manual)

Step 2: Locate and Remove the "filler Bolt"

First Jack your vehicle up by the jack points and secure the vehicle with the axle/jack stands. NEVER GO UNDER A VEHICLE SUPPORTED ONLY BY THE JACK!

Next we will locate and remove the filler bolt. In some cases the filler bolt will become completely siezed that heating it won't even work. Or the filler bolt may become stripped. If this happens to you, you don't want to this to happen with an empty transmission.

In the first image we see the bottom of the transmission looking up. The recessed bolt on the bottom is the drain. The square head on the side is the filler.

Loosen the filler by selecting the proper wrench (not an adjustable one!) and turn the wrench counter clockwise. If the bolt doesn't let go; spray the wd-40 on the bolt and let sit for 1 hour. Still stuck. Don't force it too much as it may break. You can use a propane, or MPS gas torch to heat the housing around the bolt and then gently apply pressure to loosen it. In the picture you can see I used the wd-40

If the bolt still won't budge. Stop. Lower the car and visit a shop for service in rare cases the transmission must be removed and taken to a machine shop.

If you get the bolt loose. Unscrew it, but don't remove it completely.

Step 3: Remove the Drain Bolt.

Use the same process you used to remove the filler bolt to remove the drain bolt. On my vehicles, the drain bolt is a perfect fit for a 3/4 inch drive ratchet.

Loosen the drain, place the drain pan under the transmission and then remove the drain bolt allowing the oil to drain.

Step 4: Clean the Magnet and Remove the Filler Bolt.

The drain bolt usually has a magnet on it that catches the metal shavings. Clean them off really well. you can see how filthy it was on this vehicle. I'm betting it's been over 50,000 Kms for this vehicle.

Now remove the filler bolt. (you waited until now to keep the oil from draining too quickly and splashing all over.

Step 5: Replace the Drain Bolt.

Replace the drain bolt, thread it on by hand first for at least 3 complete revolutions to make sure you haven't cross threaded it. Then tighten it with the ratchet. Lastly tighten it with a torque wrench to the manufacturers specifications. If you are unaware of the settings call your dealer and they will tell you.

Step 6: Fill the Oil. Close the Filler Bolt.

Add your gear oil back into the gearbox using the oil pump. Fill the oil into the filler until the oil reaches the level of the filler (It will ooze back out.)

replace the filler bolt once again turning it by hand for a few revolutions. then tighten it and torque it using a torque wrench.

Step 7: Drive

Clean up and take the car for a test drive.

Please take your used oil to a recycling depot. It's free in many areas. Old oil can be processed into Diesel fuel or plastics among other things.

Canadian Tire accepts old oil at their Auto service bays.