Why Your Maxima Makes a Clunking Noise (And How to Stop It)

How to Fix Transmission Issue

If you're experiencing strange noises or behavior from your 2020 Nissan Maxima's transmission, you're not alone. Owners have reported a range of unsettling symptoms that can be tricky to diagnose. The key is a methodical approach, starting with the simplest and most common causes identified by other drivers. As one owner shared their diagnostic struggle: "They said they couldn't get the car to make the noise. So I said thanks, paid my $30 and as I was leaving the car made the noise again for a split second." This highlights the intermittent nature of some of these problems, requiring patience during diagnosis.

Symptoms

Owners describe a variety of concerning sounds and sensations related to the drivetrain. The most frequently reported symptom is a distinct clunking noise, often felt during gear changes, acceleration, or when coming to a stop. This isn't a smooth shift; it's a pronounced, metallic thud that can be heard and felt through the chassis.

Another common report is a metal popping sound. This differs from a clunk and is often described as a sharper, higher-pitched "ping" or "pop," sometimes occurring when turning, going over bumps, or during light acceleration. Alongside these noises, many drivers simply report a general strangeness in how the transmission behaves—unexpected hesitations, jerky power delivery, or the feeling that the CVT is "searching" for the right ratio instead of operating smoothly.

A critical point from owner reports is that these issues are often intermittent. The problem may not happen during a short test drive, making it incredibly frustrating to reproduce for a mechanic. As illustrated by the owner quote above, the noise can appear randomly, even as you're leaving the shop. Finally, while less directly tied to internal transmission failure in the data, some reports mention leaks. Any fluid leak underneath the center of your vehicle should be investigated immediately, as low transmission fluid can cause a host of operational issues and noises.

Most Likely Cause

Based on the collective experience of owners discussing these symptoms, the primary culprit for drivetrain-related noises like clunking and popping is worn or broken engine/transmission mounts. While the data includes a mention of an "intake leak" as a potential cause, the more specific and actionable diagnosis from owners points to mounting hardware. One owner directly advised, "with the movement you could have a broken/worn mount somewhere." The engine and transmission are large, heavy components connected to your car's frame by several rubber and hydraulic mounts. These mounts absorb vibrations and control movement. When they wear out, crack, or fail completely, the engine and transmission can shift excessively under torque, causing metal-on-metal contact, pronounced clunks during gear shifts, and popping sounds as components settle or move against their restraints. This movement can also strain other connections, potentially leading to symptoms that feel like a transmission issue when the root cause is simpler.

How to Diagnose

Diagnosing a mount-related issue requires a visual and physical inspection, as electronic scanners typically won't flag a bad mount. You'll need a good flashlight, a pry bar or large screwdriver, and a safe way to look under the vehicle, such as jack stands or a ramp. Never rely on a jack alone for support.

First, perform a visual inspection. With the engine off and cool, look at the main engine mounts. On the 2020 Maxima, there are typically three or four: one on each side of the engine and a transmission mount. Shine your light on the rubber portion of each mount. Look for obvious cracks, tears, splits, or complete separation of the rubber from the metal housing. Check if the rubber is sagging or if the engine appears to be sitting lower on one side.

Next, conduct a physical movement test. With the parking brake firmly engaged and the vehicle in Park, open the hood. Have a helper start the engine. Watch the engine carefully as your helper shifts from Park to Drive and then to Reverse, applying light brake pressure each time. Look for excessive engine rock or lift—more than an inch or two of movement is suspect. You can also have your helper gently rev the engine while in Park and observe movement. Use extreme caution during this test, keeping clear of moving parts.

Finally, perform a pry test. With the engine OFF, use your pry bar to gently and carefully lift or lever the engine slightly at a sturdy point (like the oil pan, but be gentle). The goal is to see if the engine moves easily and if the mount rubber flexes as it should or if it's already collapsed. Compare movement side-to-side. A mount that is completely failed will allow significant movement with little effort.

Step-by-Step Fix

Replacing an engine or transmission mount is a serious DIY job that requires mechanical confidence, but it is achievable. The following steps outline the general process for replacing a side engine mount. Always consult a factory service manual for your specific vehicle for torque specs and detailed procedures.

Step 1: Safety First. Park on a level surface, engage the parking brake, and chock the rear wheels. Disconnect the negative battery cable. Safely raise and support the front of the vehicle on jack stands. Allow the engine to cool completely.

Step 2: Support the Engine. This is the most critical step. You must use an engine support bar or a high-quality floor jack with a flat wood block on the pad to support the engine's weight from underneath. Position the support on a sturdy part of the engine oil pan or a designated lifting point. Apply just enough pressure to take the weight off the mount you're replacing.

Step 3: Remove Obstructions. Depending on which mount you're replacing, you may need to remove components for access. This could include the air intake assembly, coolant reservoir, or other brackets. Label connectors and keep hardware organized.

Step 4: Remove the Old Mount. Unbolt the mount from the engine bracket and from the chassis or subframe. There are usually two or three bolts on each side. You may need to use penetrating oil if they're rusty. Once all bolts are removed, carefully maneuver the old mount out.

Step 5: Install the New Mount. Position the new mount into place. Hand-thread all bolts to start, ensuring they are not cross-threaded. Tighten the bolts to the vehicle manufacturer's specification in the proper sequence, typically in a criss-cross pattern. Do not fully torque them until all bolts are started.

Step 6: Lower Engine and Reassemble. Slowly and carefully lower the engine support just enough to seat the mount with the vehicle's weight on it. Then, perform a final torque of all mount bolts to the specified value with the weight applied. Reinstall any components you removed in Step 3.

Step 7: Final Check. Reconnect the battery. Start the engine and let it idle. Shift through gears while holding the brake, observing for a significant reduction in engine movement and noise. Take a short test drive to confirm the clunking or popping is resolved. As one owner noted about problem-solving, the fix can sometimes be found in unexpected places: "I would like to add that when my car started doing that, my grounds were bad. Remove your battery and check your battery to frame/transmission ground wire." While this addresses an electrical issue, it underscores the importance of checking simple connections that can cause complex symptoms.

Parts and Tools Needed

• Parts:
  • Engine Mount (Side). Part numbers vary by side (Driver vs. Passenger). An example OEM part number is 11220-9JA0A (verify with your VIN). Consider aftermarket options from brands like Anchor or Beck/Arnley for cost savings.
  • Transmission Mount. OEM part number example: 11310-9JA0A.
  • Mount Bolt Set (optional, but recommended if old bolts are rusty).
• Tools:
  • Floor jack and (at least two) jack stands or vehicle ramps
  • Engine support bar or a second high-quality floor jack with wood block
  • Socket set (metric, typically 14mm, 17mm, 19mm) and ratchets
  • Breaker bar or long cheater pipe for leverage
  • Torque wrench
  • Pry bar
  • Penetrating oil (e.g., PB Blaster)
  • Flashlight

Real Owner Costs

The cost to fix drivetrain noise varies dramatically based on the root cause and who does the work. For a worn mount, which is our primary suspect, here's the breakdown:

DIY Repair: If you have the tools and ability, this is primarily a parts-and-sweat job. A single quality aftermarket engine mount can cost between $80 and $150. A full set of three mounts might run $250 to $400. Your only other cost is your time, likely 2-4 hours for a first-timer.

Professional Repair: Shop rates make this repair significantly more expensive. A single mount replacement at an independent shop could cost $400 to $700 when you factor in 1.5-2 hours of labor at $150/hr plus the part markup. A dealership will be higher. For a comprehensive fix replacing multiple mounts, owners should be prepared for a much larger bill. One owner, discussing a different but major repair, highlighted modern repair economics: "Count on $3k today to have that done in our post-COVID world. $1,000 is the new $100 in the modern day car repair paradigm." While not for a mount, this quote reflects the potential scale of professional automotive repairs today. If a shop misdiagnoses the issue or the problem is intermittent, you might pay a diagnostic fee for no fix, as another owner experienced: "paid my $30 and as I was leaving the car made the noise again."

Prevention

Preventing premature mount failure revolves around reducing shock loads and stress on the drivetrain. Avoid aggressive driving habits like "brake torquing" (revving the engine while holding the brake) and harsh, abrupt shifts from Drive to Reverse. When coming to a stop, try to brake smoothly rather than making last-second, hard stops. Regularly inspect your mounts during oil changes for early signs of cracking or oil saturation (some are fluid-filled). Catching a deteriorating mount early can prevent the loud clunks and more expensive collateral damage. Keeping up with general maintenance also helps; a poorly running engine that misfires or shakes violently will put extra strain on all mounts.

What Owners Say

Real experiences from NISSAN owners:

Owner Experiences

"The concensus is that the factory oil is very good. I went 12,000 miles on the factory oil before I changed it and I sent a sample to Blackstone laboratories and the results came back that the oil was still good to go a bit more." — PetitFrereAccord (12,000 miles) (source)

"Then I will go back to using 0W20. I bought my 2020 HAH brand new and it now has 50,000 miles in only 16 months and car drives like the day I drove it off the showroom floor." — PetitFrereAccord (50,000 miles) (source)

"I would like to add that when my car started doing that, my grounds were bad. Remove your battery and check your battery to frame/transmission ground wire." — Kryogen (source)

Real Repair Costs

"I thought you meant that you pulled them and took them to their place. Count on $3k today to have that done in our post-COVID world. $1,000 is the new $100 in the modern day car repair paradigm." — rbuswell (source)

"So I said thanks, paid my $30 and as I was leaving the car made the noise again for a split second. The mechanics ran out and we spent the next 20 minutes trying to reproduce the noise." — Safad0 (source)

"Count on $3k today to have that done in our post-COVID world. $1,000 is the new $100 in the modern day car repair paradigm. As I mentioned, the car is not worth much money. $3k going toward a newer car is a better use of funds." — rbuswell (source)

FAQ

Q: How long does it take to replace an engine mount? A: For a skilled DIYer with the right tools, replacing one accessible side mount can take 1.5 to 2.5 hours. If it's your first time or you need to replace multiple mounts or the transmission mount, budget 3 to 5 hours. A professional shop will typically book 1.5 to 2 hours of labor for a single mount.

Q: Can I drive with a clunking noise from the transmission area? A: You can drive cautiously for a short distance to a repair facility, but it is not recommended for daily use. A failed mount allows excessive engine/transmission movement, which can strain wiring harnesses, coolant hoses, exhaust components, and even lead to a more catastrophic failure if the engine shifts too far. The noise and jerkiness will also likely worsen.

Q: Is this a common issue on the 2020 Maxima? A: Based on owner discussions, drivetrain-related noises (clunks, pops) are a reported concern. The continuously variable transmission (CVT) can exhibit its own set of behaviors, but the specific metallic clunks and pops often point to mechanical issues like mounts rather than internal transmission failure. One owner's question highlights the uniqueness of the CVT: "Do the paddle shifters make it feel like its a true 6 speed? Im having a hard time wrapping my head around the CVT transmission." This unfamiliarity can make owners more sensitive to normal CVT operation versus actual problems.

Q: DIY vs mechanic - what's recommended for mount replacement? A: This is a high-stakes intermediate DIY job. If you are comfortable supporting an engine safely, using a torque wrench, and working in tight spaces, you can save hundreds of dollars. However, the risk of improper installation (leading to immediate failure) or causing damage while supporting the engine is real. If you have any doubt, the security of a professional repair is worth the cost. The decision may also depend on the vehicle's value, as one owner pragmatically noted about a major repair: "the car is not worth much money. $3k going toward a newer car is a better use of funds."

Q: Could it be the transmission itself and not a mount? A: Yes, internal transmission issues are possible but often present with different symptoms like slipping, whining, overheating, or failure to engage gear. Mount failures are a more common and less expensive cause of the specific "clunking" and "popping" sounds. Diagnosis should always start with checking the mounts, as it's the simplest and most cost-effective possibility to rule out.

Q: What about adding a transmission cooler like some owners mention? A: One owner mentioned, "I ordered a separate tranny cooler... I have a 6MT so I might use it as a power steering cooler." While a transmission cooler is an excellent upgrade for severe use or towing to prevent CVT overheating, it will not fix existing clunking or popping noises caused by mechanical wear like bad mounts. It is a preventative measure for a different type of transmission problem (overheating and fluid degradation).