I have a 2005 2500 Laramie 4x4 with auto transmission, 27,000 miles. When towing, 4 horse trailer, fully loaded about 10,000 lb or no load 5,000 lb) engine temperature goes up, transmission overheats, and no power (lucky to be able to get 20 mph going up small hill) Even without towing, transmission seems to search for a gear General fuel mileage is terrible, loaded or unloaded, about 12.5 mpg. Have had to the dealer 3 times and they say there is nothing wrong with it, nothing shows up on their computer check and they are adamant that if the engine or transmission ever overheated it would record a code. I have an auxillary transission cooler, larger transmission fluid pan, using Royal purple transmission fluid, increased the exhaust to 5, keep the oil changed, use diesel fuel treatment recommended by the 4 wheel drive shop. Has anyone else had this problem or have any suggestions? Thanks.

 

It almost sounds like a blockage some where, the over heating engine could cause the trans to over heat. If the ecu sees high temps I know it will reduce power to try and reduce temps. The problem with the trans is I belive the ecu dont kick in till it sees 260 on trans temps, that is way to high so if it throws codes I would bet its cooked.

Is it bone stock or is anything done? Do temps only go up when towing? Are you keeping the rpm's above 1800 when you hit a hill?? Is there another dealer around?

When you put it in drive on flat ground and take off the brake does it roll?? How much throttle to start rolling? Something is draging, or blocked or causeing alot of resistance,

 

I think you are lugging the truck, low rpm,no boost, heavy load with the tc unlocked.With the tc locked the trans runs cooler and with more boost you should get lower egts.

Do a search for the mystery switch which will allow you to manually lock the tc in 3rd or 4th at lower mph,Add a Quad XZT or Smarty jr for more low end.

BTW: if you drop to 20 mph pulling a hill then you need to manually shift to second to get the rpms back up and add a little boost.

good luck

 

Sounds like the computer is in limp mode. A bad sensor in the trans. could cause this, or your computer could be completely bad. Take it back to the dealer and make one of the techs ride with you so you can show them what it's doing. Your truck should pull 10K no problem.

Nick

 

There is definately something wrong. You don't need any add ons, switches, etc. for that light a pull. At 5000lbs. you should be able to rip up that hill with no problem, and no heating. Even if your truck heated up just slightly, your high speed fan would go on and bring it to normal right away. The first thing that comes to mind with that big a loss of power is the intercooler. The intercooler on the early 05's (like mine) have plastic sides, and perhaps it is just starting to split.

 

Engine temp goes up.Up to what? Same question with trans.Any lift or real tall tires?

 

Fill out your signature so we can all see what kind of truck you have and any power improvements and so forth (gearing). Can't make an educated decision without it.