I have a 2005 Elantra GLS Automatic.
It drives well but when changing gear from 2nd to 3rd the RPM goes a little high and then with a jerk the gear shifts to 3rd gear. The jerk is noticeable but not very hard. It happens when the engine is cold and hot as well but more noticeable when the engine is cold.

I got it checked by a mechanic and he says its all fine(probably because he wasnt able to notice it since the engine was warm when he test drove the car). I got the transmission fluid changed to see if the problem goes away, but it did not help the problem remains the same. I still have the problem and can not figure out what can be done.

If anybody has a similar problem and figure out any reason, please help.

 

Swap out the two little plastic transmission sensors. "speed sensors"

It takes about 30 minutes, only requires a screw driver. Once you see the parts you;ll see how easy this is. It might fix it and it is cheap, in realte to a transmission.

I had a issue where the car threw itself into like first gear while driving!

I thought the car was shot. then I changed out the little black plastic sensors and its been running another few years perfectly.

There are two that can be changed out super easy, and parts bought at any typical auto parts store.

good luck

 

Thank you ElantraMan
I tried to find the two black plastic sensors, but I was not sure so i went to autozone shop in my area to have a look at the parts to easily recognize them and asked for transmission/speed sensor but they do not sell it as the guy on the counter told me. I will appreciate anything that would help me identifying and replacing these sensors.

 

you might have to order them from a dealership. If you can find someone at an Autozone that knows their stuff, they can print out a chart/pic showing where to find the sensors, and they should do it for free. you can take this and show it to a parts center at the dealer and they should be able to find the part and maybe even advise you on how to install it.

I ended up having to go to a dealer just to get the interior door handles for my '96 elantra.

also, double check that the fluid is full and that the right kind was used. some shops don't check after they add fluid and just assume its full b/c they went by some chart. Gotta make sure the right type is being used as well.

 

Thank you xBruce88x
I checked autozone but they dont have the part as the associate said so I checked O'Reilly Auto Part's website and got this part Dorman OE Solutions 917-606 - Auto Trans Speed Sensor | O'Reilly Auto Parts



I got two parts, Transmission speed sensor (output) and Transmission speed sensor (input), I am not sure if I need to change both these output and input sensors but after some research I concluded (for my case) I need to change the output sensor, since the output sensor is used to determine the Transfer Drive Gear rpms and then decide the optimum gear position and input sensor has to control the optimum fluid pressure during shifting.(I am a novice if I write something wrong please correct)

Hope it works, I am going to change it myself as ElantraMan said, feeling nervous since I have never worked on a car before.

 

UPDATE:
Hi all,
I replaced output speed sensor(one of the two sensors mentioned in second post) and tested the car. I find the car is running better than before, smoother gear shifts. However I am not sure if the problem is gone completely. When I press the gas pedal hard and accelerate fast i.e. when car switches gears at higher RPMs this gear change effect is noticeable (not as bad as before but definitely not normal) however if I keep accelerating constantly the gear shft is normal. Is this something normal?