I just bought a 99 qc ram 5.9l auto trans. Everything was going good until today. The check engine light came on! It started smelling like it was running rich and if it sets and idles to long it will smoke some. It is a blue/white color smoke. I took it to the autozone and had them hook it up on there machine and it read 2 codes. First code was P0420 and the second code was P0740. I think the first code is catalytic converter or something and the second code is something to do with the transmission! The transmission shifts good and dosnt slip or anything. It has a new trans in it and is full of fluid. What could be causing all this to start happening. Thanks for the help in advance!!!

 

First one is about catalytic converter efficiency, do you still have one?? Might want to check.....

Second code is whining about no RPM drop when the Torque converter clutch is 'requested' (demanded??) by the PCM. indicates a bad solenoid in the trans. Take it back to where you bought it, and suggest to them that their trans rebuilder got a bad part....... You CAN change these yourself, but, if you have only had it for a bit, you shouldn't have to.

Something else to consider, did they plug the post-cat O2 sensor back in when the did the trans?

 

Do you have to take transmission out of the truck to change that soleniod? Could the P0420 code cause it to smoke a litte or will that be something else? Sorry for all the questions this is my first Ram. It still runs and drives great just that little pesky light is buggin me! What is that solenoid called? Thanks!

 

I think the 420 code is being set because it IS smoking..... Have you checked your plenum? (do a search, there are literally hundreds of threads about that particular problem.... I am quite surprised we don't have on on the first page....)

The TCC solenoid comes paired with the overdrive solenoid, I do not believe they are serviceable separately... I have no clue what they call them, your best bet is to get them from the dealer anyway.... which will also show you were they are. You have to drop the valve body out of the trans to change those.....

How long have you had the truck?

 

I just bought it sunday from a private seller! It hasnt acted up or anything until today and the light came on! I dosnt run bad and idles good and goes down the road good. It didnt smoke or anything when I went and drove it and looked it over before I bought it. I guess I just bought a lemon truck. That is how my luck always goes. Is the blue/white smoke gas or oil? I will check the plenum out tomorrow. As for the trany I will get back in touch with the guy and find out where he got the trans done at. My next ? is will it be ok to drive or do I need to park it?

 

Blue is generally oil. (which indicates a badly blown plenum... or, a cheap PCV valve. ) I would have a look down the throttle body, and see what you see. If it looks ok, buy a PCV valve from the dealership. (about six bucks.)

Pay attention to your trans, take it out somewhere that you can get it up to 55 or so, but, there isn't a lot of traffic. (trying to pay close attention to the tach on a busy street really isn't a good plan....... )

As you accelerate, watch the tach, there should be a reasonable drop for the 1-2 shift, another drop about the same for the 2-3 shift, a small drop when TCC engages, and then a fairly substantial drop for the 3-4 shift. With stock tires, you should be right around 1500 RPM at 60MPH......

Now, would you be so kind as to send me some warm weather?

 

Ok thanks! I had it on the highway today and it did run close to 1500 RPMs at 55 to 60 mph. It shifts nice and smooth through every shift and cruises out good. When I am running down the road and get on it, it will go into passing gear with no problems. It still has plenty of power. When I take it out of overdrive it gears down a gear just like it is supposed to. The 4x4 works like it is supposed to. I will have to check it all out tomorrow when I have some daylight!

If I could send you some warm weather I would. It has been nice down here in GA until yesterday and it started raining.

 

Tomorrow is a holiday. Time to spend some time with family.

Thanks for the thought on the weather anyway. It has been below freezing up here of late. I hate winter.

 

Yeah true about the holiday and family, but I wont work on it long. Im just gonna try to figure out the problem. I will work on it another day.

 

LOLOL

I am going to ask your wife how long you REALLY spent out there.