I'm hoping someone can help me with this one. My 2000 Elantra has some transmission issues. If I drive around for a while my transmission will get stuck in 3rd gear. If I'm on the highway it'll downshift into 3rd really hard and stay in that gear. If I let the car cool off for a little bit it's fine again. It also shifts hard into 2nd gear sometimes. And also when I'm coming to a stop it'll downshift into 1st really hard. The transmission seems to get really hot. The fluid level is good. The fluid looks clean. Any ideas? Thanks

 

How many miles are on the car? Was the trans ever serviced (fluid flush)?

 

It's got 150,000. Yeah I always change it on time. I even use the $6.50 a guart Hyundai fluid. lol I forgot to mention the car has had this problem for about 2 years. I've neen changing it more often since this problem started. About once a year.

 

I had the problem with an old Volvo once. It would downshift into 3rd too easy after driving on the highway, and wouldn't come out. I finally figured out it was a heat problem and added a transmission cooler... problem solved. Trans coolers are cheap insurance and easy to install. Get one from eBay, get the biggest one you can fit.

 

I agree. A good trans cooler would be a good investment.

 

That's a great idea! Thanks I'll try it

 

My Tucson has a factoy external trans cooler. A cheap fix would be to salvage the trans cooler from a wrecked Tucson (one with rear end damage, not front). A junkyard or maybe eBay is where I'd look for one.

 

This is a well known issue with Elantra automatic trans. The 4 speed trans uses a speed sensor to shift in overdrive. This isn't the same speed sensor used for the speedometer. It's an other speed sensor only used by the transmission. Whenever this fails the overdrive will not engage. I'll look in my notes to give you the sensor # and try to post images of the sensor. The sensor is worth approx 80$

 

Thanks that would be great. I have a parts car so I would apreciate that.

 

The sensors I was talking about are the pulse generators. To select the right gear the TCU (Trans Control Unit) uses the feedback from theses 2 sensors and the throttle position sensor. Since you have a part car you can start with theses 3 sensors.
I don't want to bring bad news but the rough downshift from 3 to 2 and 2 to 1 may mean that your Pressure Control Solenoid Valve isn't working properly. This one is located inside the transmission.
If the sensors doesn't fix your problem you may need to have it checked by a transmission professional.

Good Luck!