Down Shifting

[melrich]

Hello, I have 01 superduty F250 4 wheeler, cold air, 4in exhaust, superchip programmer. Last weekend I hooked up 26 ft enclosed trailer, 7000 lbs and headed across the state of SD on I 90 from Sioux Falls to the Black hills. I had the program in performanc towing. Towing at 65mph to 70 mph in OD I had a lot of down shifting buzzing the motor upto 3100 rpm. I was heading into a 30 mph quarting wind. How hard is this on the motor? I only averaged 9.8 mpg on the hole trip. Coming back was a lot better on down shifting on the hills. Is this about what I can expect from this truck? Just driving around I get about 13.5 mpg. When it shifted down and runnig for 2 or miles the service engine light would come on, then would go off after about 5 miles, is this normal or do I have to get it scanned. Thanks for help.

 

[DaveBen]

You need to get it scanned.

Dave

 

[JRJ04]

well first of all, if you had it on performance tow (which is the 90hp setting...the middle one) then i really think youre just asking for trouble. Even though it says you are ok towing in that tune up to *** lbs...factor in that headwind and hills and i can almost say with certainty that youre exceeding the limit. if you are going to tow anything, its really best to leave it on the lowest setting.

Secondly, do you happen to have any gauges that monitor your egt, boost, and transmission temp? The check engine light could have been a multitude of things, but if i had to guess it was probably something like overboost since it went back off.

Others will chime in, but i think its a good general rule of thumb that if your transmission is constantly downshifting and looking for a lower gear, its best to take it out of O/D.

Hope this helps!

 

[BIG JOE]

What Jourdan sez.. X2