Hi guys I'm new to this and this is my first diesel. I have a 2003 ram 3500 dually Automatic transmission . It ran great up until about a month ago. The transmission cooler(heater) must've had a leak and my radiator fluid mixed with my transmission fluid. I caught it literally like an hour after it happened as I was doing a radiator flush just because I decided to change the radiator hoses as they felt kind of hard. Well I flushed the fluid changed the filters and topped her off. Ran amazing after that. Now of all sudden my transmission won't go into gear -no reverse no drive .... just park revs and acts like it's in neutral. But if I wiggle the fuse box while it's on it'll shift into gear. Or if I shut it off and turn it back on it'll move for like a 1/4 mile then act up again and just sit there in any gear.

Thanks for the help guys and sorry ahead of time if I made any rookie mistakes on my first post lol

 

This happened to mine. Its in limp mode likely. For me, the filter got clogged (a result of smoking some of the internal clutch packs). Maybe as simple as the filter being replaced, up to you need to have the transmission overhauled.

 

[QUOTE=2-Stroke;3332725]This happened to mine. Its in limp mode likely. For me, the filter got clogged (a result of smoking some of the internal clutch packs). Maybe as simple as the filter being replaced, up to you need to have the transmission overhauled.[/QUOTE

so I ended up putting in an AUX transmission cooler and replacing all the lines. Blew out the OE transmission cooler. I also replaced the speed sensor, pressure solenoid and transducer ...new filter then topped off with ATF 4 and my truck is now running great .....we'll see what happens ..... thanks for the reply