Most recently, automakers have focused on simplifying car maintenance in hopes of making life easier for their consumers. Car manufacturers have attempted to create “lifetime” parts, including sealed transmissions. What does this mean for maintaining your car? We asked Mechanic what you need to know.

Why Do We Replace Transmission Fluid?

While you drive, friction materials from your transmissions clutches and bands will make their way into your transmission fluid. Traditionally, auto manufacturers suggested having the transmission fluid changed every 60,000 to 90,000 km. Modern cars, however, have extended service intervals for many reasons. They include:

Simplify vehicle ownership by asking the owner to do less maintenance

• Reducing the amount of “used” transmission fluid in landfills
• Increase maintenance intervals which reduce overall costs

How Do We Replace Sealed Transmission Fluid?

Replacing the fluid in a sealed transmission can be a bit tricky, as these systems are designed to be maintenance-free or require minimal maintenance. However, if the fluid needs to be replaced due to contamination, overheating, or other issues, you can follow these general steps:

Steps to Replace Sealed Transmission Fluid

1. Check Manufacturer Instructions: First, consult your vehicle’s owner manual for the recommended fluid change interval and specific instructions, as sealed systems often don’t have a dipstick or easy access for fluid changes.
2. Prepare the Necessary Tools and Equipment:
   • Transmission fluid (make sure it’s the type specified in your vehicle manual)
   • Funnel with a long spout or specialized transmission fluid pump
   • Wrenches and screwdrivers
   • Drain pan
   • Vehicle jack and jack stands (if necessary)
   • Gloves and safety glasses
3. Lift the Vehicle (if needed): If there’s no access to the transmission fluid pan from the top, you may need to raise the vehicle using a jack and place it on jack stands for better access to the transmission.
4. Locate the Transmission Fluid Drain and Fill Plugs:
   • Many sealed transmissions don’t have a dipstick but do have a drain plug and a fill plug (often located on the side of the transmission).
   • If your car has a sealed transmission, it may require a specialized tool to access these plugs.
5. Drain the Old Transmission Fluid:
   • Drain Plug: Place a pan underneath the transmission, and use a wrench to remove the drain plug. Allow the fluid to completely drain out (this may take a few minutes).
   • Check Fluid Condition: Examine the old fluid for signs of metal shavings, burnt smell, or dark coloration, which may indicate serious issues with the transmission.
6. Replace the Filter (if applicable):
   • Some transmissions have an internal filter that should be replaced during a fluid change. If yours does, you may need to remove the transmission pan to access the filter. Note that not all sealed transmissions have a serviceable filter.
7. Add New Fluid:
   • Fill Plug: Once the old fluid has drained, use a funnel or fluid pump to fill the transmission with the recommended amount of new transmission fluid through the fill plug.
   • Check Fluid Level: In many sealed systems, the correct fluid level is achieved when the fluid starts to overflow from the fill hole. If your vehicle has a special checking procedure (like needing the engine running), follow the manufacturer’s instructions carefully.
8. Replace the Drain and Fill Plugs: After the transmission is filled with the proper amount of new fluid, replace and tighten the drain and fill plugs securely.
9. Check Fluid Level:
   • After adding the fluid, start the vehicle and let it warm up to operating temperature.
   • With the engine running, check the fluid level again. Some vehicles require you to check the fluid level with the engine in gear, while others may require you to check it while in park. Follow the specific instructions in your manual.
10. Test Drive: After completing the fluid change, take your vehicle for a short test drive to ensure the transmission operates smoothly, with no unusual slipping or hesitation.
11. Check for Leaks: After the test drive, inspect under the vehicle for any signs of leakage from the drain or fill plugs.

Important Notes:

• Sealed Transmission Service Intervals: Not all sealed transmissions need fluid changes. Some manufacturers recommend that the fluid be changed every 60,000 to 100,000 miles, while others claim it’s lifetime fluid. Always check your owner’s manual for specific intervals and maintenance requirements.
• Tools and Professional Help: Some sealed transmissions require specialized tools or professional equipment for fluid changes, especially for vehicles that do not have a simple drain plug or have a very specific fluid refill procedure. If you’re unsure, it may be best to take the vehicle to a qualified mechanic.

If the system is truly sealed and does not have drain and fill plugs, you might need a special pump or tool to remove and add fluid, and some manufacturers may require that only certified dealers perform this task.

Can You Check the Transmission Fluid Yourself?

Even for seasoned DIY car owners, replacing the transmission fluid in a sealed transmission is not something you want to attempt. A minor mistake could lead to major costs, or worse, permanent damage to your vehicle. You may also risk voiding any warranty you have by attempting to service the transmission yourself. Either way, it’s best to contact your local Master Mechanic if you suspect something is up with your sealed transmission.

Signs Your Sealed Transmission Fluid Needs Attention

If your transmission is suffering from poor fluid quality, you’ll typically notice one of the following symptoms:

• A grinding sound when driving or switching gears.
• A delay when shifting

Since many drivers are holding on to cars for longer, the aftermarket is poised to service these vehicles and keep them ‘on the road’ for as long as possible. Automakers are aware of this and there is pressure on them to produce longer-lasting vehicles. There are other sealed components on your vehicle and we wouldn’t be surprised to see the number increase.

For now, it’s essential for you to understand what a sealed transmission is and how to recognize if there is an issue with yours. Remember anything in a vehicle can break down, even if the automakers claims it’s a “lifetime part”.