While the length of time that your transmission fluid is going to last will vary by car and by driver type, you should check on your fluids every 15,000 miles or so.
Knowing when your manual or automatic transmission is having problems is a challenge if you're not a car expert, but there are signs to look for. If you're noticing some of the following problems, then it doesn't mean that the worst is happening but it could mean you need an expert's help.
Watch for these four issues.
1. Watch for Fluids
When you see any leaking transmission fluid, it doesn't always mean the worst. Your transmission has a lot of moving parts that require a lot of lubrication to function. All that lubrication keeps the system from overheating which leads to a rapid breakdown of the part and could even cause the transmission to seize up.
If you don't have enough fluid in your transmission, you're going to face some critical issues later on. If you see it leaking, you might have just overfilled your line. However, it could be leaking from the transmission, leading you to have inadequate lubrication.
When you see leaking, head over to a specialist to diagnose the issue. It's much cheaper to have your transmission repaired now than to be replaced later. You may just need a new seal to keep the transmission fluid contained.
If it's something more serious, you can have it fixed before you end up stranded by the side of the road. Transmission fluid has a sweet odor and tends to be bright red in automatic transmissions. This is what to look for when you're spotting leaks.
2. Watch For The Warning Light
If you see your check engine light come on, that could be an after effect of transmission issues.
Your warning light is a catch-all warning that there's a problem with your car. It's not going to give you in-depth information about what's going on with your car. You'll need a mechanic to diagnose the real issue.
It doesn't often mean there's something wrong with your transmission. Your transmission problems could coincide with the check engine light. There could also be another system causing the transmission to act unusually.
Take your car to a transmission specialist to rule out problems with your transmission.
If you find that there's something else wrong, it will likely cost you less than it does to fix a transmission. The cryptic warnings can be decoded by a trusted mechanic and help inform what you need to do next.
Again, while your check engine light isn't often the first sign that you have a problem with your transmission, it could be part of another issue. This could trickle down to your transmission and impact your ability to drive your car safely.
3. Shifting Delays Are a Sign
As you drive your car, you shift from gear to gear as the conditions of the road changes and as you change the speed. Going faster on rough ground is different than going fast on smooth ground. In fact, you might need to be in the same gear to get out of dense gravel as you do to speed on the highway.
Delays between gear shifts happen in a lot of modern vehicles due to electronic issues and the sensors under stress or suffering delay. However, when a vehicle experiences a problem with the transmission, it may feel the same as the electronics issue.
Pay attention to your shifting as you climb hills or speed up on highways. If something feels off, trust your gut and bring it in to a specialist. You might be able to stop an issue before it gets out of hand.
Shift delays are challenging to diagnose or to fix. Talk to a transmission expert or to your mechanic to have this repaired. It'll require special attention to have this adequately diagnosed and treated.
4. A Lot of Dark Dense Fluid
Transmission fluid becomes denser over time. Much like engine oil, as it runs through your system, it tends to accrue dirt and debris and to break down in general. Thicker and darker fluids are normal over time, but if you've changed your fluid fairly recently, watch for serious changes in its makeup.
Your transmission fluid should be changed every 60,000 miles or so depending on the vehicle that you drive. Your service manual is going to give you a more accurate measure of how long your fluid should last.
If it's been a while since you've replaced your fluid or you never have, consider doing it when you see color and viscosity changes. When things become excessively dark or thicker than they should be, that means that it's not going to do its job. When the fluid becomes too thick, it's not going to keep your components lubricated, which is going to lead to breakdown and wear that causes failure later on.
This will lead to overheating which is going to further deteriorate the fluid and could even change the levels of fluid in your system.
Automatic Transmissions Can Surprise You
When driving a manual transmission, you're in much closer contact with your transmission than an automatic driver. However, that doesn't mean that you can listen to your car for it to tell you about its problems. When you pay attention, you can avoid costly repairs later on.
For more details on how transmission services work, check out our guide.