Updated on December 5, 2025, for Placentia Super Service in Placentia, CA.
Your automatic transmission is one of the most complex and expensive systems in your vehicle — and in many cases, replacing it can cost more than an engine. That’s why early detection matters. The sooner you spot a sign of trouble, the more likely you’ll prevent a major (and costly) repair.
Below, we break down the most common transmission symptoms, what each one means, and when it’s time to bring your vehicle to Placentia Super Service for a professional inspection.
Common Questions About Transmission Problems
“Why is my transmission shaking?”
“What causes gears to slip?”
“Can low transmission fluid ruin my transmission?”
“Should I worry about a burning smell from my car?”
These are the exact questions drivers in Placentia, Yorba Linda, Fullerton, and Anaheim ask us every week — and the answers often point to one of the seven issues below.
1. Grinding or Shaking When Shifting Gears
A healthy automatic transmission should shift smoothly and quietly. If you feel grinding, shaking, or a jarring sensation when the vehicle changes gears, your transmission is sending an early warning.
Common Causes
1. Worn clutch packs or gears
2. Dirty or degraded transmission fluid
3. Internal wear that worsens over time
If the shaking becomes more intense or happens more often, don’t wait. Transmission issues rarely fix themselves — they escalate.
Grinding or shaking during shifts is often a sign of internal wear or failing transmission fluid. Get it inspected right away to prevent expensive damage.
2. Car Won’t Engage or Respond When in Gear
If you shift into Drive or Reverse and the car hesitates — or doesn’t move at all — that’s a problem.
Possible Reasons
1. Low or degraded transmission fluid
2. Worn internal components
3. Electrical or computer (TCM) issues
4. A failing solenoid
Sometimes, resetting the vehicle’s computer (disconnecting the battery for ~30 minutes) can help if it’s a software issue, but if the problem continues, it needs a professional diagnosis.
A delay or failure to engage gears usually means a fluid issue or an electronic problem in the transmission. Get it checked before it leads to complete failure.
3. Whining, Humming, or Clunking Noises — Especially in Neutral
Strange noises are one of the most common transmission-related questions we get from drivers.
What These Sounds Can Mean
1. Whining or humming: Low or deteriorated fluid
2. Clunking: Possible internal damage
3. Noise in Neutral: Worn bearings or gear teeth
Transmission fluid loses its protective qualities over time. When lubrication breaks down, friction increases — and that friction destroys parts.
New noises — humming, whining, clunking — often mean your transmission fluid is failing or a component is worn. Have it checked immediately to prevent further damage.
4. Burning Smell Coming From the Vehicle
A burning smell is never normal. With transmissions, it almost always points to overheated or degraded fluid.
Why This Happens
1. Low fluid due to a leak
2. Using the wrong fluid for your vehicle
3. Old fluid full of debris and friction material
Once the fluid overheats, it loses the ability to lubricate moving parts. That leads to wear, sludge buildup, and eventually a total breakdown.
A burning smell usually means your transmission fluid is overheating — a major warning sign that requires immediate attention.
5. Gears Slipping While Driving
If your RPMs jump unexpectedly or your vehicle feels like it momentarily loses traction or power, your transmission may be slipping.
Why This Is Serious
1. The computer may not be signaling gear changes properly
2. There may be worn internal parts
3. Fluid pressure may be low
A slipping transmission can put you in danger, especially when merging into traffic or climbing hills.
Gear slipping is a safety issue. If your transmission slips while accelerating, have your vehicle inspected immediately.
6. Low or Leaking Transmission Fluid
Transmission fluid is typically bright red when clean and dark red or brown when old. If you see red spots on your driveway, that’s a leak — and transmission leaks never fix themselves.
Why Low Fluid Is Dangerous
1. Causes excessive heat
2. Leads to internal wear
3. Can destroy the transmission if ignored
Leaks often come from worn gaskets, seals, hoses, or the transmission pan. These repairs are usually minor if caught early.
If you see red fluid under your car, get it checked right away. Low fluid leads to overheating and catastrophic transmission failure.
7. Check Engine Light Is On
Your transmission has sensors that monitor temperature, pressure, and shifting patterns. If something feels “off,” the system signals the engine computer, which triggers the Check Engine light.
Even if your vehicle seems to drive fine, the earlier the issue is diagnosed, the better your chances of avoiding a major repair.
A Check Engine light can indicate a transmission issue. Have it scanned early to prevent minor problems from becoming big ones.
When Should You See a Transmission Specialist?
If you experience any of the symptoms above — shaking, noises, slipping, burning smells, leaks, delayed engagement — it’s best not to wait.
Most transmission failures start small.
Most major repairs start with a minor symptom.
And the most expensive jobs could have been prevented with early inspection.
Get Peace of Mind at Placentia Super Service
Our ASE-certified technicians help drivers throughout Placentia, Yorba Linda, Fullerton, Brea, and Anaheim stay safe and avoid costly transmission failures.
If you’re noticing any of these automatic transmission problems, we’re here to help.
📞 Call Placentia Super Service
📍 Visit us in Placentia, CA
🛠️ Let our team inspect the issue before it becomes expensive.
Your car will tell you when something’s wrong — and we’ll help you understand what it means.