4 Ways to Prevent Transmission Overheating & Avoid Failure

Heat is the number one cause of premature transmission failure. Not manufacturer errors, or even defective parts. It accounts for approximately 90% of all automatic transmission failures.

Need a replacement transmission? Get an estimate for replacement transmissions and local installation. Look up your transmission model by vehicle make and model.

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In This Guide

Excessive transmission heat is responsible for the start of many transmission problems including; ruptured seals, cracked gears, slipping transmission bands, failed bearings, inoperable solenoids, and delayed clutch engagement. You name the part, and too much heat can cause it to break.

This silent killer has claimed the service life of countless transmissions, and it could be wreaking havoc on your vehicle every time you put it in gear. An overheated transmission can often go unnoticed until it’s too late and something breaks.

The most common causes of overheating include solenoid problems, fluid leaks, low fluid levels and burnt/old fluid. Other heat generating factors are if you live in a hot climate, often drive in stop and go traffic and/or tow heavy loads with your vehicle.

How Automatic Transmission Fluid Cools a Transmission

It contains chemical additives that provide lubrication and the pressure to change gears, but its primary function is heat removal. The spinning gears, expanding springs, and whirring turbines generate friction as they move about.

This friction produces a lot of heat, which can cause stress fractures, varnishing and other forms of damage to the internal components if it isn’t dealt with quickly.

For this reason, it is formulated to absorb the heat as it flows through the moving parts. It then carries the heat out of the transmission to the radiator, where the hot fluid is forced through a special cooling chamber that uses aluminum fins to extract heat from the ATF.

As air flows through the radiator, the heat is dissipated and the cooled fluid is then piped back to the transmission for another round. If it isn’t able to remove and expel heat through the factory transmission cooler fast enough, the transmission will overheat and damage will start to set in.

Fluid Life Expectancy vs Temperature

Over time, heat breaks down the organic compounds inside the fluid, causing it to take on a darker red, then brown, then black color. It also becomes thinner, which significantly reduces the amount of heat that it’s able to carry away from the moving parts.

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If your transmission isn’t serviced (new fluid + filter) every 20,000 to 30,000 miles or once every 12-18 months, the fluid will become ineffective, and the normal operating temperature will increase.

The ideal operating temperature of transmission fluid is 175 degrees. Overheating occurs after the temperature surpasses 200 degrees, and the failure rate doubles for every additional 20 degree increase after that.

So if you drive the vehicle with the fluid temperature at 240 degrees, your transmission will develop significant problems and fail 4 times sooner that it would have otherwise. Fresh, clean fluid on the other hand, will make it run cooler, shift better, and last longer.

Fluid Temperature & Damage

  • 220-degrees = varnish forms on metal surfaces
  • 240-degrees = seals harden
  • 260-degrees = transmission bands and clutches begin to slip
  • 295 degrees = seals and clutches burn – call a tow truck

For every 20 degree reduction in fluid temperature, your transmission’s lifespan will approximately double!

Low fluid levels will also cause the transmission to overheat, rather quickly. Without enough ATF to remove the heat, the temperature can skyrocket past 260-degrees, resulting in a slipping transmission, along with serious damage to the clutches, bands, and torque converter.

To keep this from happening, check your transmission fluid level once a month, or every two weeks if you spend a lot of time on the road. And don’t forget to leave the motor running when you check it, otherwise you won’t get an accurate reading.

How to Prevent Transmission Overheating

1) Check Transmission Fluid Often

You should check your vehicle’s fluid at least once a month in order to spot issues such as a low fluid level or worn out dirty/burnt fluid. This will allow you to fix these early warning signs before they cause serious transmission problems that can damage or destroy your transmission.

In addition to checking the level and quality of fluid using the dipstick, be sure to look under your car occasionally for stains on the driveway or transmission pan to make sure that your fluid isn’t leaking.

2) Change the Fluid on Schedule

Your vehicle’s transmission fluid should be changed every 30,000 to 60,000 miles. You can change it yourself or have a transmission shop flush it from your vehicle.

If you drive in a hot climate, a lot of stop and go traffic or haul heavy loads, the fluid should be changed more often than the suggested range – every 15,000 to 20,000 miles for example. That way your transmission is always running on fresh, effective fluid that will keep it cool.

3) Add an External Cooling System

Your vehicle’s radiator is responsible for cooling down the fluid, so be sure to change the coolant inside it every 2 years or so.

If you haul or tow heavy loads, the radiator alone may not be enough to keep it cool and you should consider installing an external transmission cooler. A stacked plate cooler for example is easy to install and attaches to the front of the radiator.

4) Add a Deep Pan

If your transmission has overheated, then it is worth considering adding a deep pan. A deep pan allows you to add more fluid to your vehicle, which helps spread out the heat and remove it from the transmission faster. Aluminum pans dissipate heat better than those made of steel.

When to Install a Transmission Cooler

Towing causes a serious amount of strain/heat buildup. So does the constant up-down shifting the occurs when you’re crawling through traffic, or driving in hilly/mountainous terrain.

If you regularly do this type of driving, then you need to seriously consider having an aftermarket transmission cooler installed. Most are designed to work in tandem with the manufacturer’s original transmission cooler, and they provide increased fluid capacity so that more heat will be removed, faster. To keep your transmission temperature from exceeding safe levels, this is the best way to go.

Other Transmission Heat Sources

Worn transmission bands, clutches, and solenoids can also cause your transmission to overheat. If the part isn’t functioning correctly, it can generate excess friction heat and overwhelm the fluid.

Even though just one part is worn or broken, the high temperature can do things like warp the valve body, and destroy the torque converter internals. So if you can help it, try not to drive the vehicle until the transmission is repaired.

Need a replacement transmission? Get an estimate for replacement transmissions and local installation. Look up your transmission model by vehicle make and model.

What Transmission Do I Have?

What to Read Next

Over to You

We’re interested to know – has your transmission overheated? If so, how did you fix it? Let us know by leaving a comment below!

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Leave a Comment

Debbie

Well it’s gonna be an interesting next few days as I attempt to diagnose the damage to my C6 Tranny in my 96 Rexhall Aerbus. Someone cut the brake and and tranny line. What a mess. I wasn’t sure how much tranny fluid this was to take. I thought I had looked it up as this has never had the tranny serviced. It has 30k miles on it. The auto parts store is a bit confusing because even with them having access to other people and the internet I find that they know less about trannies than I do. First I’m checking for a plugged filter. Which is s huge possibility. We never lost reverse or first. It runs great in reverse. Will let ya all know what I find.
Debbie

Bd

Hi my Allison 2200hs get hot since i went last week on highway.

Mechanic found brass and aluminum inside oil . He want replace whole transmission.

Whats cause this heat up problem as this problem suddenly came over?

Oil level is good. Oil is in good shape. Cooler return line has ample flow.

Any suggestions wellcome

Eddie S.

owner of a 1999 sierra 1500. go up to about 55mph and the rpm jump up to about 2200. feels like it struggling hard. i just got the trans. rebuilt about 3 mnths ago. man and i dont want to spend that amount again. Anyone have a clue?

Bd

How did you fix this problem?

Bob Eberenz

Have a ‘08 Silverado. Transmission temperature is usually around 150 to 175 when I’m on the highway. Goes up quick if I’m stuck in traffic or idling 200 to 210 or so. When I check fluid it looks ok but it seems like it might be overfilled. Could this be causing temperature to go up ?

Pete

I have 2006 Honda Ridgeline. I was towing my ultra lite rv trailer and my transmission hot light came on. I shut down for approximately one hour and proceeded. Stayed under 45mph and drove it home. No heating no problems at all. What now? Obvious to me is get expert to check. What should I expect? Is transmission repairable or even needs repair? Would adding a transmission cooler be recommended?
Thank you

Susiku mwanangombe

I just changed the transmission fluid but the vehicle is failing to engage other gears and I temperature is moving up so fast

Justus Chandrabose

You should use the transmission fluid as per the specification of your car vin number and purchase from the agency, replace filter too..

William Clements

truck runs fine when cold. When it gets hot after running a while the transmission binds, wont move forward or reverse. Has transmission cooler. Please, if you have any ideas. I’ve had it in the shop twice, over $1000. and same problem

John

I have o7 chevy silverado changed torque convertor, solonid, catalytic converter, new senors, computer & when i plow a couple small bussiness the transmisson gets hot what could cause this

Justus Chandrabose

Purchase oil from the agency as per vin number and replace the filter too..