Hello, I've recently run into some problems with my automatic 2005 Neon SXT. I bought it at 102k miles and only drove it around 3,000 miles before it gave me any issues.

I started to pull of of my driveway in reverse and the trans slipped a bit. Once at the end of my driveway I put it in Drive and it went nowhere. I've had this problem before on a different vehicle so I turned it off, put it in neutral and pushed it back up the driveway. After opening the hood I noticed that my transmission fluid was at the very bottom for adding while cold and that the radiator fluid had an orange oily color and was really thick.

I did some research online and found out that trans fluid can mix into the coolant via a cracked radiator so over the next few days I did some repairs with my dad.

We completely flushed out the cooling system and replaced the radiator and thermostat. Also we drained the transmission fluid from the pan (luckily it was still red and not milky) and got a new filter. After putting everything back in I took it for a test drive and it worked perfectly. Shifted between all the gears nice with no slipping between reverse, drive, neutral, etc. And the only leak was from the fittings on the radiator not being tightened up completely because we didn't think about it before putting it in. It was easy enough to do and completely stopped before my test drive. Advanced Auto Parts shipped us the wrong radiator the first time so when we got the second it was almost dark outside, hence our rushing and forgetfulness.

Now this morning, roughly 10 hours after finishing repairs, I put it in reverse to go to school. No slippage until I tried going into drive and the problem started all over again. I figured out that it will go into gear occasionally but you have to play with the shifter a bit and it will occasionally go into a gear. Also after running the car about 10 minutes before going anywhere to defrost the ice on my windshield, I noticed that the thermostat wasn't working (it was the night before). The radiator fluid is still green (I mixed it 50/50 with distilled water) and the transmission fluid is still full (put in 4 quarts of Mopar ATF +4 like the Haynes Repair Manual said to use). However I did notice little bubbles in the fluid on the dipstick.

I'm completely out of ideas and haven't been able to find anything through google about fixing this or the possible problems. Any help is greatly appreciated.

 

You don't have any incorrect gear ratio or loss of prime codes?

 

How would I go about checking that?

 

I was told by a friend it could be the valves sticking. He recommended Lucas Transmission Fix. Has this worked for anyone? If so how much should I use?