I own a 1996 Ram 1500 with the 318 and 46RE tranny. I would like to buy an OBDII code reader to help with diagnosing my transmission but I would like to know first if it will do any good because my check engine light does not come on. Are the error codes only generated when a check engine light(on) condition occurs or can an error code occur without the check engine light ever coming on?
Thank you in advance

 

The trans can set codes, but, I am unsure if JUST a trans code will turn on the CEL. What is your trans (not?) doing?

 

A good scanner will read any stored coses. Some of them are counted a certain number of times before it sets CEL such as 2-3 shift error.

 

It does everything you can think of. This morning I started it cold to show someone what it was doing and it drove like a champ for about a mile. 1st,2nd,3rd,4th. Everything was fine. I pulled up to a stop sign and listend to it downshifting and it sounded fine to me. I gave it some gas, 1st,2nd then it didnt change to third and the RPM'S kept crawling up so I turned around and started going back home. same thing 1st, 2nd then it left 2nd and felt like it was in nuetral. I coasted to a store and let it sit a few minutes with key off. Started it up and no reverse,1st,2nd or drive. I let it sit a few more minutes and i got it to go into first. Luckily I was almost home but I still had a steep hill to make it up. I had to turn it off several times and let it sit about a minute and it would stay in first long enough to get 30 feet up the hill. After about 5 times doing that i made it into the driveway. I changed the fluid and filter a couple days ago hoping the filter was clogged but that wasnt the problem.
Yesterday I left the truck at a friends house after limping the truck there and he hooked it up to a computer after I left. He drove it 3-5 miles and had no trouble with it, no codes. I dont know what kind of scanner he was using because he borrowed it from someone else. I also didnt get any information regarding any codes which may have been stored up to that point. He said his friend "cleared them".
I am a little nervous about buying a code reader if I wont see any codes.

 

When you changed fluid and fileter, what fluid did you use?
Did you check in while in Park or Neutral?

Common issue with these trannys is the governor pressure sensor and governor solenoid. These are located on bottom of valve body. Common fix it to clean sensor (or replace) and upgrade governor solenoid.

Also, you may want to consider adding a drain plug in tranny pan the next time you have it off.

I bought a Snap-On MTG 2500 on e-bay. Checks more stuff than one can imagine, and shows more than ordinary OBD scanner. Shows lots of live data as well.

 

I checked it with engine at operating temp. nuetral and ATF-4 fluid. I have been reading this forum so much my head is spinning. Everytime I talk to my friend he wants me to wait until his friend comes over to check it with the computer. I think Im doing exactly what your recomending since it's a cheap enough fix and if all else fails I have some new parts to put into a used tranny from a junk yard.

I still want to buy a code reader too but im not sure if it's going to do any good unless the reader reads real time and stored codes. Do you know if code readers can read stored codes and realtime or do I need more expensive models for that?

edited

 

Great....you did it correctly. Just wanted to make sure as a lot of folks check in Park like other vehicles.

I suspect governor solenoid and pressure sensor.

 

Thank you!!

 

The snappy 2500 scanner will hand you all sorts of real-time data. You can get 'em for a hundred or so on ebay.

 

I believe you have more serious issues than the gov. If you don't have 1st,2nd,3rd, or rev. That means that the direct drive clutches in the tail housing are not engaged...ie( spring that holds clutch pressure is shot, and or clutches). Only a loss of third or reverse is a front clutch failure...ie, piston seals (when the fluid is cold it will work due to thicker viscosity helping it to maintain pressure.) The gov only is used to time shifts by applying more pressure to the shift valves. The kick down valve applies pressure on the opposite side of the valve to hold off shifts longer as the gas pedal is pressed harder....or force a down shift.

One thing I would have checked is the trans line pressures. I would say a rebuild is probably needed.