My sisters 2004 Neon SXT suddenly started acting up on her way to work. She said it started to smell hot and started jerking and not driving smoothly then finally going into limp mode. She parked it off to the side and we towed it home.

I checked out the car on the side of the road. There was a large pool of transmission fluid under the vehicle. I scanned the codes and I got P0700 which I believe is the generic transmission problem code. That popped up twice in the scanner. I also go P0871 OD pressure sensor circuit, P0734 gear ratio error in 4th and p0702 gear ratio error in 2nd.

The car will not move in drive or reverse. The car would move in first and third gear.

I finally got the car in my garage to look at it. There is almost no fluid on the transmission dipstick. There is transmission fluid pooled on top of the bell housing, along with the steering rack, drivers side axle, lower firewall and the bottom of the car is coated with fluid.

I could not see any place where fluid was coming from. I'm thinking it may be pressurized by the way everything is coated with fluid. I'll probably fill the trans back up and try to see where the fluid is coming from unless anybody has a better idea of what the problem is.

 

I'd guess those codes came up because of the loss of fluid. I'd look around and see what you can find.

 

I filled up the transmission like it says to do in the factory manual and ran the shifter through the gears, with no leaks. I checked the fluid level and everything looked good, and the codes went away.

I restarted the car and put it in neutral and the 4 quarts I put in poured out from the bottom in about 30 seconds. I couldn't see where it was coming from since the car was on the floor, but I plan on doing it again with the car up to try and pinpoint from where it's coming from but I have a feeling the trans will have to be pulled anyways.

Anybody have a idea?

 

May have a better idea if we know where it's coming from.

 

This is exactly what happened on my 2004 SE when the trans cooler inside the radiator blew. Same thing while driving too, just as you described

Same thing trans fluid pouring out when I put some in.

What was happening was the coolant had mixed with the trans fluid and there was so much fluid in the trans, it comes out the overflow.

By the way, that ruined my trans and radiator... and about 1 week and $1200 later had a rebuilt trans and new radiator

 

From what I have read, it seems to be a pretty common problem. I rechecked the coolant reservoir and it was empty. They dye they use in the coolant, along with the bad location of the reservoir made it look like it was full.

I'll pressure test the cooling system, that should verify that bad trans cooler is the problem.

I'll install a new radiator, flush the cooling system and the transmission along with a new trans filter and hopefully no damage was done.

 

If the car was driven around with an ATF/Coolant mix, I can only hope for the best for you with the transmission.

 

This happened fast without any other symptoms like a slipping transmission, jerking, etc., so hopefully the radiator failed immediately so that minimal damage was done to the transmission.

If she's going to keep the car for a few more years and this ends up being the problem, I'll put a MT radiator in it along with a external cooler.

 

It doesn't take long for that mixture to eat the transmission up. I too, hope it was immediately. Good call on the external cooler.

 

If the trans does grenade itself there are plenty of used ones in the area. The car is not worth enough to warrant a rebuilt unit.

I'll tear into the car monday and hopefully get it moving on its own again.