2020 Nissan Maxima Transmission Shaking or Whining? Here's How to Fix It

Here's a comprehensive guide on transmission replacement for your 2020 Nissan Maxima. Many owners experience issues with their transmissions, leading to costly repairs. As one owner stated, "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 (https://maxima.org/forums/4th-generation-maxima-1995-1999/712690-gasket-seals.html). We'll cover common symptoms, potential causes, diagnostic steps, repair procedures, costs, and preventative measures to help you address this issue effectively.

Symptoms

One of the most common symptoms related to transmission issues in your vehicle is vibration or resonation. This can manifest as a shaking sensation, particularly at certain speeds or during acceleration. Owners have described this vibration as being felt through the steering wheel, seats, or the entire vehicle.

Another frequently reported symptom is a banging or clunking noise coming from underneath your car. This noise often occurs when shifting gears, especially between drive and reverse or during automatic gear changes. The banging can be intermittent or constant, and its intensity can vary depending on the severity of the transmission problem. This can also be linked to shifting problems.

Shifting problems are a significant indicator of potential transmission trouble. These problems can range from difficulty shifting into gear to delayed or erratic gear changes. Some owners have experienced slipping gears, where the transmission momentarily disengages and then re-engages. Others have reported harsh or jerky shifts, where the gear change feels abrupt and jarring.

A whining sound emanating from the transmission is also a common symptom. This sound can be subtle at first, but it often becomes louder and more noticeable over time. The whining may be present at all times or only during specific conditions, such as when accelerating or decelerating. The pitch of the whine can also change with vehicle speed.

Most Likely Cause

Based on owner reports, the primary cause of transmission issues in your vehicle can be related to an intake leak. While seemingly unrelated, an intake leak can disrupt the engine's air-fuel mixture, potentially leading to improper engine performance that indirectly affects the transmission. This is because the engine and transmission are interconnected systems.

An intake leak can cause the engine to run lean, meaning there is too much air and not enough fuel in the combustion mixture. The engine control unit (ECU) may attempt to compensate for this lean condition by adjusting various parameters, including the transmission's shift points and torque converter lockup. These adjustments, while intended to maintain optimal engine performance, can place undue stress on the transmission and cause the symptoms described earlier. The lack of proper air-fuel mixture can cause the computer to try and compensate, causing added stress to the transmission.

The vacuum leak creates havoc with sensors, readings and ultimately affects the transmission. Although not directly a transmission malfunction it causes it to act up.

How to Diagnose

Diagnosing transmission issues in your vehicle can be challenging, but a systematic approach can help pinpoint the problem.

1. Check Transmission Fluid Level and Condition: Start by checking the transmission fluid level using the dipstick. The fluid should be at the proper level and appear bright red or pink. If the fluid is low, dark, or smells burnt, it indicates a problem.

2. Listen for Unusual Noises: Pay close attention to any unusual noises coming from the transmission area, such as whining, clunking, or banging. Note when these noises occur (e.g., during shifting, acceleration, or deceleration).

3. Observe Shifting Behavior: Carefully observe how the transmission shifts gears. Note any delays, harshness, slipping, or erratic shifting patterns.

4. Scan for Trouble Codes: Use an OBD-II scanner to check for any stored trouble codes. While some codes may directly relate to the transmission, others may indicate engine-related issues that could indirectly affect transmission performance.

5. Inspect for Leaks: Check for any signs of transmission fluid leaks around the transmission housing, seals, and cooler lines.

6. Check the speed sensor: As mentioned by TallTom (https://maxima.org/forums/5th-generation-maxima-2000-2003/712819-pnp-sensor-replacement-6-speed-maxima-question.html), the speed sensor might be at fault. The speed sensor might be accessible from the engine bay and it is an easy thing to check.

Tools Required:

• OBD-II Scanner
• Jack and Jack Stands (for under-vehicle inspection)
• Wrenches and Sockets
• Transmission Fluid Dipstick
• Drain Pan

Step-by-Step Fix

Addressing transmission issues in your vehicle often requires a combination of troubleshooting and repair steps.

1. Address Intake Leaks: The first step is to identify and repair any intake leaks that may be present. Inspect the intake manifold gaskets, vacuum hoses, and throttle body for cracks or leaks. Replace any damaged components.

2. Transmission Fluid Change: If the transmission fluid is old, contaminated, or low, perform a transmission fluid change. Use the correct type of fluid specified for your vehicle. "It's always a good idea to change the output shaft seal when you change out the CV axle. I would also recommend to do a few drain and fills on the transmission to get all the old fluids out. it's common for people to never even service their transmissions. the fluid should be red not brown..." - uptownsamcv (https://maxima.org/forums/5th-generation-maxima-2000-2003/712966-2000-nissan-maxima-se-need-help.html).

3. Inspect and Replace Sensors: Check the transmission speed sensors and other related sensors for proper function. Replace any faulty sensors. As one owner shared: "I vaguely remembered shift linkage around it but wasn't sure if that black connector sensor was accessible from above or not." - TallTom (https://maxima.org/forums/5th-generation-maxima-2000-2003/712819-pnp-sensor-replacement-6-speed-maxima-question.html)

4. Check the Valve Body: One owner mentions the valve body as a potential cause for transmission issues: "I had a Mercedes that exhibited those symptims and it was the switching matrix in the transmission (valve body) that was failing." - BrianShaw (https://maxima.org/forums/8th-generation-maxima-2016/713402-gas-pedal-randomly-stops-working.html).

5. Consider a Transmission Cooler: Some owners have added an aftermarket transmission cooler to help prevent overheating, especially if they frequently tow or drive in hot conditions. "I ordered a separate tranny cooler, Mishimoto, but never wired up the fan." - uptownsamcv (https://maxima.org/forums/5th-generation-maxima-2000-2003/713000-aluminum-radiator-off-ebay.html)

6. Professional Diagnosis: If the above steps do not resolve the issue, it is recommended to seek professional diagnosis from a qualified mechanic.

Parts and Tools Needed

• Transmission Fluid (Specific to your vehicle model)
• Intake Manifold Gasket
• Vacuum Hoses
• Transmission Speed Sensor (if needed)
• OBD-II Scanner
• Wrenches and Sockets
• Jack and Jack Stands
• Drain Pan

Real Owner Costs

The cost of addressing transmission issues in your vehicle can vary widely depending on the severity of the problem and whether you choose to DIY or seek professional help.

• DIY Transmission Fluid Change: The cost of a DIY transmission fluid change can range from $50 to $100, depending on the type of fluid and filter used.

• DIY Intake Leak Repair: Repairing an intake leak yourself may cost between $20 and $100 for parts, such as intake manifold gaskets and vacuum hoses.

• Professional Transmission Fluid Change: A professional transmission fluid change can cost between $150 and $300, including labor.

• Professional Intake Leak Repair: Having a mechanic diagnose and repair an intake leak can cost between $200 and $500, depending on the complexity of the repair.

• Transmission Replacement: The most expensive option is a full transmission replacement, which can cost between $3,000 and $5,000, including parts and labor. As one owner noted, "$3k going toward a newer car is a better use of funds." - rbuswell (https://maxima.org/forums/4th-generation-maxima-1995-1999/712690-gasket-seals.html).

Prevention

Preventing transmission issues in your vehicle involves regular maintenance and proactive care.

• Regular Transmission Fluid Changes: Follow the manufacturer's recommended maintenance schedule for transmission fluid changes.

• Address Intake Leaks Promptly: Inspect and repair any intake leaks as soon as they are detected.

• Avoid Harsh Driving: Avoid aggressive acceleration, hard braking, and frequent towing, as these can put extra stress on the transmission.

• Monitor Transmission Temperature: If you frequently tow or drive in hot conditions, consider installing a transmission temperature gauge to monitor the transmission's operating temperature.

• Regular Inspections: Have your vehicle inspected regularly by a qualified mechanic to catch any potential problems early.

What Owners Say

Real experiences from NISSAN owners:

Owner Experiences

"That is simply unbelievable unless they are totally incompetent. I had a Mercedes that exhibited those symptims and it was the switching matrix in the transmission (valve body) that was failing." — BrianShaw (source)

"I vaguely remembered shift linkage around it but wasn't sure if that black connector sensor was accessible from above or not. It sounds like I will have to find a way to safely get underneath for the swap, or just let the code keep randomly reappearing." — TallTom (source)

"I remember seeing last year when I had the airbox out to swap out a knock sensor. I vaguely remembered shift linkage around it but wasn't sure if that black connector sensor was accessible from above or not." — TallTom (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)

"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 fix a transmission issue?

A: The time required to fix a transmission issue can vary depending on the complexity of the problem. A simple fluid change or sensor replacement may take a few hours, while a transmission rebuild or replacement can take several days.

Q: Can I drive with transmission problems?

A: Driving with transmission problems can cause further damage and potentially lead to a complete transmission failure. It is recommended to address transmission issues as soon as they are detected.

Q: Is transmission replacement a common issue on the 2020 Nissan Maxima?

A: While not the most frequent issue, transmission problems do occur in the vehicle. Regular maintenance and addressing issues early can help prevent major problems.

Q: DIY vs mechanic - what's recommended?

A: Simple tasks like fluid changes and sensor replacements can often be done DIY if you have the necessary tools and experience. However, for more complex issues like transmission rebuilds or replacements, it is recommended to seek professional help from a qualified mechanic. Considering the potential costs involved, ensuring the job is done right is crucial.