I have a 2002 F350 crewcab 4x4 duel wheels 7.3l engine Auto trans 4:10L diff. I pull a 15,000 pound fifth wheel on the east coast elevation at sea level. I did some up grades new turbo, intake, exhaust, guages, new chip, added a 4" lift and 35" tires. my first problem was my transmittion overheated, so rebuilt the trans new metal parts and rerouted tran lines out of radiator new v10 trans cooler new front bumper of of a newer model (lets more air in) moved license plate out of way added new electric fans. this thing pulls great and hooks up good in the mud however when i went west to NM, CO and back as I get around5,000 feet still in VA the engine now over heats. as soon as I pull over or get on a down hill grade it cools off very quickly. This is my gut feeling when I changed my tire size I reduced the RPM's by 165 (according to the gear calculater) so the engine is now lugging this combined with the altitude is causing my overheating problem. this is what I am thinking about doing and would like some feed back

1. changing the gear ratio (front and back)to 4:55 according to the gear calculator it will put my RPMS about 30 more than where I started

2. possably having the chip reprogramed for towiing

3. im open for sugestions

4. Is a 165 change in rpms alot for a diesel

 

welcome to diesel bombers a good site and good people and theirs been talk of the inefficency of electric fans especially in a pulling situation and are you towing anything when it overheats im sure somebody else will have something to say on here

 

It was overheating with stock fan before I changed to electric over heats only when towing and at altitude around 5,000 feet and above

 

how hot are your egt's when your overheating are you pushing the fuel through it and have you ever had your radiator rodded or cleaned

 

when in overdrive I start losing power cant keep up to speed, in NM for 200 miles maybe a 1,000 feet of elevation change in that distance RPMs drop egt start to go up never above 1100 I back off the throttle at that point the engine starts to overhear if i shift out of overdrive bring up the boost to run around 2500 to get back up to speed after about 5 minutes or less it will start to overheat. No I have not i have changed the thermostat, i have around a 150,000 miles on it

 

make sure the intercooler is free of debris and allows airflow thru the fins

also I bet yer electric fan doesnt move near the CFM as the stocker did

 

intercooler is clear changed fan to get more airflow it stopped the trans from overheating I just moved it to the engine

 

when was yer last glycol flush?

 

just before i went on my trip i had it completely serviced and again when it overheated i also added the engine ice to the radiator to help it run cooler

 

are you running yer A/C during all this???

AC is bad during towing on passes, I roll my windows down and turn AC off