How To Change Manual Transmission Fluid

Servicing A Manual Transmission is a Beginner Level Repair for Most DIYers. Here’s Everything You Need to Know to Change Manual Transmission Fluid In Less Than An Hour.

• DIY Difficulty Level: Beginner
• Time Required: less than 1 hour
• Tools & Materials: 

1. Drain pan
2. Ratchet
3. Socket (possibly a specialty socket)
4. Funnel

What Is A Manual Transmission Service?

Unlike an automatic transmission service that requires removing the drain pain and replacing a filter, servicing a manual transmission is a much easier job. While a manual transmission service didn’t make it onto our list for the easiest repair jobs for a DIYer, you don’t need many tools or extensive vehicle repair knowledge to change manual transmission fluid. This is an easy, low-cost maintenance item that can lead to expensive repairs if not performed properly and as recommended. 

All that’s required to change manual transmission fluid is draining and refilling the gear oil, which is similar to how you service a transfer case or axle differential. Performing regular preventive maintenance such as a transmission service will help keep your car on the road… even for a million miles! 

Is It Safe to Drive with Old Transmission Fluid?

The fluid used in a manual transmission is a heavy-duty gear oil, which tends to last for a long time. Except for extreme circumstances, driving with old transmission fluid isn’t a safety concern, but in a worse-case scenario, it could lead to serious transmission damage and/or leave you stranded with a broken-down vehicle. 

What happens if I don’t do this? How bad could things get?

If you don’t change the manual transmission fluid at recommended intervals as recommended by the manufacturer, it could cause excessive wear and tear on the transmission gears. At a minimum, this could affect shifting noticeable by gears that are hard to engage. If not addressed, the gears could become damaged, which is a much more expensive problem than a standard transmission service.

In short, why is this job important?

All oils are designed to lubricate moving parts, and over time, the viscosity of these oils break down leading to reduced effectiveness. Rebuilding or replacing a manual transmission is an expensive repair, but changing the fluid is quick, easy, and cost effective. 

When to Change Manual Transmission Fluid?

How often should you do this service?

This varies by automaker as well as vehicle type and severity of duty, but most cars with a manual transmission should have the fluid serviced every 60,000 to 100,000 miles. If you don’t know if the fluid has been changed, you can do a visual inspection to see the condition of the oil, which you can check by removing the fill plug and putting a makeshift dipstick (like a screwdriver) into the hole. The oil should be light in color and be close to the fill hole.

How do you know when it’s time to have this done or do it yourself?

This is a very easy DIY job, but as laid out in Step 2 of this How To guide, the condition of the drain and fill plugs are important in determining whether or not to attempt this job in your driveway. If either of the plugs are damaged or hard to remove, you should have a professional look at your car. You don’t want to drain the oil from the transmission only to find out that the fill plug won’t come out, and then you’d need to have your car towed to a shop.

What Are Common Symptoms Indicating You Change Manual Transmission Fluid?

• Mileage determined by manufacturer’s preventative maintenance schedule
• Grinding noise when shifting gears
• Fluid leaking from transmission (address leak and change fluid)
• Visual inspection shows dark fluid

How To Change Manual Transmission Fluid

Step 1: Safely jack up vehicle and remove wheels and tires

Just as you would for a tire rotation, start by jacking up the vehicle on a level surface and place jack stands in a safe location to support the vehicle. Be sure to use a tire chock in front of and behind the front tires to protect against the vehicle rolling. 

Step 2: Remove transmission fill plug

As mentioned above, before you drain the fluid, you should remove the fill plug to make sure it isn’t damaged. If you can’t remove the fill plug, then you shouldn’t drain the fluid as you’ll have no way of putting fluid back into the transmission. Sometimes the drain and fill plugs will require a specialty socket, so make sure you’re using the proper tool, too.

Step 3: Position drain pan under transmission and remove drain plug

If the fill plug comes out easy, then it’s time to get ready to drain the fluid. Start by positioning a drain pan directly under the drain plug. Keep in mind that as soon as you remove this drain plug, fluid will begin to pour out of the transmission. 

Once it’s out, inspect the drain plug. These are usually magnetic, so if there’s a lot of buildup on the plug, that could suggest excessive wear is going on with the gears. If there’s no buildup, clean the drain plug and then reinstall.

Step 4: Add fluid

This can actually be the most challenging step when you change manual transmission fluid as it can be difficult to add fluid without making a mess. On front-wheel drive cars, it is sometimes possible to use a rubber hose to act as a funnel extension so you can add fluid from the engine compartment. 

The parts store should be able to tell you how much fluid and what kind of fluid your specific vehicle requires, but you’ll know that the transmission is topped off properly when fluid starts to come out of the fill hole. 

Step 5: Reinstall wheels and tires, and lower vehicle

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