Why does my Transmission stop working when it gets hot? 4 Reasons

Transmission problems can manifest in several ways. And each symptom it displays is a pointer to what could be the leading cause of the problem. Transmission works cold but not hot, and transmission shifts hard when cold but fine when hot are two different problems that look alike. However, they are caused by different things.

This article will discuss why transmission shifts fine until it warms up, what causes low transmission temperature, and if the transmission can round too cold. By the end, you can confidently tell why a transmission works fine until it warms up.

transmission acts up when hot

Why does my transmission stop working when it gets hot?

There are several reasons why a transmission shifts fine until it gets hot. The most common reasons a transmission works fine on cold but not hot are worn-out parts, fluid leaks, and low fluid. You can rectify these problems by doing regular maintenance like fluid and filter changes and patching of leaks.

1. Low transmission fluid

The transmission fluid is likened to human blood. Without it, the transmission will not shift smoothly. If the fluid gets lower than where it is supposed to stay, it’ll cause gear slipping and will also cause the gears to grind against each other. When that happens, you’ll experience transmission slippage, and the grinding may cause accelerated wear on the bearings and gears, which could cause catastrophe.

It’s essential to regularly check your transmission fluid to ascertain the level. To do this, remove the transmission dipstick and clean it with a rag or cloth. After that, reinsert it and pull it out. Check the level of oil on the dipstick to see the current level of the oil. Usually, the oil should be very close to or at the full mark. If it is below the low mark, top the oil. As common as adding transmission fluid is, it could be all you need to fix this problem.

2. Fluid leaks

Another common reason both automatic and manual transmissions are hard to shift when hot is fluid leaks. If there’s a leak in the system, it’ll cause low tranny fluid, leading to transmission slippage, transmission overheating, bearings and gears grinding against each other, and accelerated internal component wears.

Fluid can leak from seals, gaskets, or even the oil pan. The two primary symptoms of fluid leaks are low fluid levels and fluid dropping from anywhere in the system, especially from the oil pan gasket. To check if you have leaks, lift the vehicle so you can easily slide underneath and visually inspect the oil pan for leaks. If you see oil dripping anywhere from the oil pan, fix it immediately.

3. Worn out parts

Under normal conditions, as your transmission ages, the internal parts will start wearing out. The gears will begin grinding against each other, causing gear slippage. The wear can cause all manner of problems, depending on which part is wearing out. Worn-out parts, along with low transmission fluid, can cause transmission stops working when warm.

The worn-out parts should be replaced for optimal performance. Inspecting worn-out transmission parts is a tedious job that requires technical know-how. Hence, you need to consult a mechanic for this. The mechanic will drop and disassemble the parts to identify and replace the worn-out parts.

4. Lack of regular maintenance

Prevention is better than cure. And car maintenance aims to prevent issues that could lead to catastrophic damage. Maintenance on the transmission includes washing oil filters and pan, inspecting and changing oil seals and gaskets, and changing damaged parts. Regular maintenance on your transmission prevents poor shifting, gear slipping, transmission overheating, and even transmission breakdown.

transmission stops working after a few minutes

What affects transmission temperature?

Several different factors will affect your transmission temperature and cause system overheating. These factors include;

  • Too much transmission fluid
  • Low transmission fluid
  • Worn-out internal transmission parts
  • External factors (too much stop-and-go driving, extreme uphill grades, high humidity/heat, et cetera)
  • Burnt/old/dirty transmission fluid
  • Overheating engine
  • Your driving habit (spirited driving, overloading the vehicle, et cetera).

Why does my car shift hard until warmed up?

As I pointed out at the beginning of this article, manual or automatic transmission that will not shift until warmed up, and transmission works fine when cold and malfunctions when hot are two different issues caused by different things. You have seen why transmission runs fine when cold; now let’s see why it only runs fine when warmed up.

Transmission shifts hard until warmed up typically happen because the transmission fluid is too cold to enable smooth shifting. Extreme cold temperature does not only affect how the fluid flows in the tranny. It also affects how the internal tranny components interact with each other. Just like the way you shiver during extreme cold weather conditions.

Can a transmission run too cold?

Extreme cold weather conditions can affect all the fluids in your vehicle. And the transmission fluid is no exception. If the ambient temperature is extremely cold, it’ll affect the transmission fluid. And if the transmission fluid is too cold, your car may not shift gears smoothly.

The cold fluid will cause gear slipping, transmission shifting hard when cold, and several other issues. These issues will normalize once the transmission warms up.

How do you warm up an automatic transmission?

Whether you have an automatic or manual transmission, when the ambient temperature is too cold, start the vehicle and allow it to idle for a minute or two before engaging the gear. This allows the cold engine and transmission fluid to circulate to every nook and cranny part of the engine and tranny. Afterward, engage the gear and let the vehicle idle for 30 to 60 seconds before driving.

Remember, if the ambient temperature is freezing, the vehicle may not shift properly until it gets hot.

Final Words

The transmission acts up when hot is typically caused by several factors. To be precise, the most common causes are fluid leaks, low leaks, worn-out internal parts, and lack of regular maintenance. You can rectify these problems by topping the transmission fluid, doing regular scheduled maintenance, and fixing leaking areas on the tranny. You can diagnose your transmission yourself or take it to a mechanic for proper diagnosis and repair.

Osuagwu Solomon

Osuagwu Solomon is a certified mechanic with over a decade of experience in the mechanic garage, and he has over five years of experience in the writing industry. He started writing automotive articles to share his garage experience with car enthusiasts and armature mechanics. If he is not in the garage fixing challenging mechanical problems, he is writing automotive repair guides, buyer’s guides, and car and tools comparisons.

Recent Posts