Signs Your Automatic Transmission Is About To Fail

Posted by on Tuesday, March 26th, 2013

The general public doesn’t know much about automatic transmissions. I could take that statement a step further and say the same thing applies to many mechanics.  There is something about automatic transmissions that scares people away. While we can’t expect everyone to be an automatic transmission expert, we do expect you to recognize the signs your automatic transmission is about to fail. Here are some easy to recognize symptoms.

Something you never want to see! A broken transmission.


Overheating: Heat is by far the automatic transmission’s worst enemy. Heat destroys more transmissions than everything else put together. So here is a fact you should remember; the ideal maximum transmission temperature is 200 degrees. For every 20 degrees you go above 200 you reduce the expected life span of the transmission by a factor of 2. Simply put, at 220 degrees you can expect ½ the life span, at 240 a ¼ and at 260 it is reduced to 1/8th.  When a transmission gets hot, it gives off an odor. You might think it would smell bad, like sweaty feet, but it has a sweet smell to it. If you smell something funny, pull over and give the transmission time to cool down. When transmission fluid gets hot, it expands like water. When a transmission gets too hot, it often spits fluid out the vent at the top of the transmission. These are two warning signs you should look out for. The best way to monitor your transmission temperature is to invest in a temperature gauge. The best gauges will also include a warning light. Gauges are easy to install and are relatively inexpensive.

Fluid. I recommend you periodically check the fluid level in your transmission, just like you do when you check the level of oil in your engine. A low fluid level is a good sign that something is wrong. Transmissions do not consume fluid the way a motor does. If the fluid level is low something is wrong. Also check the color of your fluid. Transmission fluid can be either red or green. The fluid should be light in color and almost translucent. If your transmission is a dark color you have a problem. Dark fluid is usually a sign that the fluid has been overheated.

Inspect the level of your transmission fluid


Debris in Fluid. Pull the dipstick on your transmission. Hold it up to the light. If you see any debris in the fluid, we have a major problem. The fluid might glitter like glass. It shouldn’t and what you are seeing is most likely metal shavings. The next step is to pull the transmission pan and inspect for further debris.

Slipping. Transmissions are designed to have a little bit of slip in them. Just enough so that when you shift from one gear to another it doesn’t throw you into the back seat.  If it takes more than 1 – 2 seconds to shift from one gear to another we have a problem somewhere. It could be a sign that a filter is clogged, a pump that is losing pressure or a spring in the regulator that has failed or broken. Or it could mean that your transmission is totally toasted.

debris in your transmission pan is never a good sign


Noises.  An automatic transmission should be fairly quiet. There should be no grinding noises. No banging noises. No whistling noises. If you hear anything like this stop and investigate.

Off course we all hope to catch a problem before it destroys our transmission. Sadly that is not always the case.

If you’re  too late in catching a problem and are faced with the decision to replace your broken transmission, I advise you to consider using a re-manufactured transmission over a rebuilt one. Re-manufacture transmissions often include upgrades and modifications for common problems the factory should have fixed in the first place.  They generally also include a much better and longer warranty. Long live your automatic transmission!

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