How do you know when to change tranny fluid

Recently I have just changed the oil and had a flush too due to moisture buildup.

I am wondering when i should change my tranny fluid?

Currently i have about 65k on the car and its a 99 elantra

My dad just had a new transmission put on the car about a year ago.

I checked the fluid and its a transparent/light pinkish color.

I heard you only change it when its 1. low 2. burnt or dark colored 3. smells burnt.


Is this true? and got any ideas on how to prevent moisture buildup in my oil pan?

The guy at the place said to take it on long drives atleast once or twice a month and to let the car warm up on cold mornings

Moisture build-up in the pan is prevented by taking the occasional longer drive. It takes at least 30 minutes to fully warm up the oil at this time of year. Once the oil is warmed up, in a running engine, moisture and other volitile contaminents (ie, partially burned hydrocarbons) will 'boil' off and get sucked through the PCV valve and be burned in the engine.

Short drives where the oil never fully warms up is where the moisture (from condensation and blow-by gases) builds up.

As for the transmission, changing the fluid and filter every 2 years is frequent enough to prevent trouble. This is good for cars that see trailer towing or city and heavy traffic driving.

Long-distance highway driving is easier on a transmission than city driving.


If the car is driven quite infrequently,for example, 5000 miles/year), or sees lots of highway driving, that figure can be extended to up to 4 years.

In your case, you can safely leave it for at least another year, probably longer.

BTW why did the transmission fail last year? Often, installing an aftermarket transmission cooler can help extend transmission life.

Moisture build-up in the pan is prevented by taking the occasional longer drive. It takes at least 30 minutes to fully warm up the oil at this time of year. Once the oil is warmed up, in a running engine, moisture and other volitile contaminents (ie, partially burned hydrocarbons) will 'boil' off and get sucked through the PCV valve and be burned in the engine.

Short drives where the oil never fully warms up is where the moisture (from condensation and blow-by gases) builds up.

As for the transmission, changing the fluid and filter every 2 years is frequent enough to prevent trouble. This is good for cars that see trailer towing or city and heavy traffic driving.

Long-distance highway driving is easier on a transmission than city driving.


If the car is driven quite infrequently,for example, 5000 miles/year), or sees lots of highway driving, that figure can be extended to up to 4 years.

In your case, you can safely leave it for at least another year, probably longer.

BTW why did the transmission fail last year? Often, installing an aftermarket transmission cooler can help extend transmission life.
I think it failed to switch gears properly or something. All i know is whenever we drove it it was very very hesitant and often stalled at lights and stop signs. also when driving it would often shake the car.

btw i heard that trans fluid can last anywhere from 30k to 50k miles? is that true?

I dont drive my car alot. probably 3-5k a year.

btw i heard that trans fluid can last anywhere from 30k to 50k miles? is that true?
It can easily last that long.

It depends on the use. With lots of easy highway miles, that kind of mileage is easily attainable. However, city driving, heavy traffic, trailer towing and hot weather use all can shorten fluid life.

Regular changes every 2-4 years is preventive maitenance. It helps prevent problems. People often leave the fluid in there longer, and the trans will continue to work fine, but the chances for expensive problems increases.

When you 'change' the fluid and filter, there is some fluid, (as much as half the fluid) which is not actually changed because it sits in the torque converter, cooler lines etc and does not drain out. Regular changes ensures that at least most of the fluid is not too old.

Also, if the fluid is never changed, nasty debris can accumulate in the nooks and crannies of the transmission inside, already to break loose and screw things up. Regular changes helps keep the internals clean.

I dont know if this is myth or fact but i heard that after your car has about 75k miles on it, its not a good idea to change of flush the tranny because if you do it could damage it.

im not really sure how it could but thats what ive been told. Ive also been told unless its brown or burnt smelling just leave it.

any ideas?

i know everyone has there own ways and stuff but im just trying to see the most common/popular way to do it.