The lifespan of a vehicle’s automatic transmission ranges wildly, with some requiring replacement at 100,000 miles, and others lasting for over 300,000. That difference more than doubles the life of a car or truck.
Most drivers wonder how to make transmission last longer. The best thing to do is stick to a consistent maintenance schedule appropriate for your vehicle.
In this guide, discover the optimal maintenance and care schedule for your automatic transmission. With our expert checklists at each interval, you can keep your transmission running well for years to come.
What Is An Automatic Transmission?
The transmission is the system in a car or truck that transfers power from the engine to the wheels, through the gearbox.
An automatic transmission is calibrated to reflexively change to the correct gear in response to changes in driving conditions. In contrast to a stick shift, an automatic transmission doesn’t require the driver to manually shift gears.
Automatic gearboxes make driving easier, reduce accidents and improve fuel efficiency.
How To Keep Your Transmission Healthy
There are several methods drivers can use to keep their automatic transmission systems healthy. Most automatic transmission care falls into three categories:
Getting accurate, specific information on your transmission model
Using the right transmission fluid
Sticking with an evidence-based care and maintenance schedule
Consider the following best practices in each category.
Consider Your HDV’s Automatic Transmission Type
Different transmission types have different transmission maintenance requirements. You can find your vehicle’s transmission type in its owner’s manual, or by using NHTSA’s VIN lookup service. Automatic transmission types include:
Planetary Gear (Torque Converter) Automatic Transmission
This system of “orbiting” gears uses targeted gear ratios to adapt to different conditions, enabling smooth, steady gear shifts.
Dual-Clutch Transmission (DCT)
This high-performance transmission system uses two clutches to manipulate gears simultaneously, allowing for lightning-fast gear shifts.
Automated Manual Transmission (AMT)
This fuel-efficient, low-maintenance transmission requires greater driver engagement, as the driver is meant to manually shift gears with a clutch pedal and lever.
It also incorporates ECUs to automate clutch engagement when necessary.
How To Choose The Right Transmission Fluid For Your Commercial Vehicle
Every vehicle’s manufacturer specifies the type of transmission fluid compatible with the vehicle. Those specifications outline the parameters of compatible fluids’ chemical compositions and performance.
To find these specifications, look for the OEM recommendations for your vehicle's make and model number. If you're unsure of your truck’s model or manufacturer, you can find that information using your vehicle's VIN.
Note that, while all recommended fluids will be compatible, some will enhance performance more than others. Consider severe duty fluid if your work puts high demands on your torque.
Allison Transmission Fluid Standards
An Allison Transmission requires fluid that meets its TES requirements. When a manufacturer's fluids meet the TES formulas and quality standards, those fluids are compatible with the transmission. Allison Transmission recommends the following fluids for commercial trucks, heavy-duty vehicles, and off-highway use:
TES 439: Mineral-based fluid with industry-standard fluid change intervals.
TES 353: Synthetic, high-performance fluid with extended drain intervals and enhanced temperature stability and performance.
For more standard highway driving, TES 668, TES 468, TES 295, and TES 389 are recommended.
Automatic Transmission Care: Maintenance Schedule, Tips & Tricks
To care for your commercial vehicle’s automatic transmission, follow a regular maintenance schedule. Regularly scheduled care tasks include check-ins, fluid changes, and professional servicing.
While the optimal maintenance intervals will vary by transmission type, this schedule is a useful guideline and starting point.
Check these aspects every day.
Transmission fluid level and color.
With the truck parked and level, run the engine, then pull out the fluid dipstick. Wipe it dry, re-insert it to dip, then pull it out and examine the fluid's color and its level relative to the stick's "full" marker.
If it’s low, find a certified specialist to diagnose the issue.
Compare its color to the chart on the fluid’s container.
If it’s significantly lighter, darker, or muddier, that’s a sign of contamination.
Leaks.
Inspect the undercarriage for drips or puddles.
Note any burning smells, low fluid level, and fluid discoloration.
Temperature gauge.
Measure the temperature of your transmission’s fluid with a digital diagnostic scanner or an infrared thermometer.
Make sure the tool is properly calibrated.
If the temperature is over 195 degrees F, or above the overheating level listed in the owner’s manual, take the truck in for inspection.
While engaging in checks, listen for any unusual sounds or vibrations.
Preventative Care Tips For Your HDV’s Automatic Transmission
There are several best practices you can engage in to prevent automatic transmission damage. Transmissions can be damaged by freezing fluid, abrupt temperature changes, and undue pressure. To combat these risks, try these tips:
Come to a near-complete stop before changing gears.
Protect your vehicle's transmission fluid from extreme cold in the winter.
Park indoors or in sheltered areas.