f150cwcw

I have a 2006 F150 4.6L V8 with the 3.55 gears. When im pulling i turn the Overdrive off so i dont burn up my overdrive. When pulling on the hwy going 60mph im running a little over 2000rpms but if i go 70mph im running about 2750 rpms. Is this ok to run this high of rpms when pulling? I have heard that it wont hurt a thing running higher rpms unless you are consistantly in the redline area. Is this true? It pulls really well in 4th gear running 60-70 mph, just didnt want to hurt anything.

CrashTECH

Is it safe to tow whatever you are towing at that speed is a better question....

f150cwcw

Towing at 60 is not unsafe. I just put down the 70mph and rpm numbers so i could show how high the rpms were with the gears i have. I usually tow no faster than 60mph but im looking at taking my boat to the coast and the speed limits are 70mph. I know i dont have to go that fast but it gets nerve racking when you have a line of 20 cars behind you on a one lane road cause you are going 60 in a 70.

Ruprecht

What's wrong with using overdrive? I tow cross-country a couple times a year and use overdrive whenever I can. Seems like running higher RPM's would be worse for the trans in the long run. I only turn off O/D when on hills to keep from overheating brakes or when my truck keeps shifting from top gear to O/D and back (this is what my owners manual advises).

Thunderslide

There seems to be too many variables to really give a straight answer. Making a few assumptions about the weight and size of the towed item and that it is safe to tow at that speed. IIRC the manual says something to the effect that if it is not shifting up and down frequently leave it in OD if it is shifting often turn it off. Now, it does not talk about what "frequently" would be described as.

f150cwcw

Well if i had the 5.4 L V8 like you do, i wouldnt be asking this question cause i would have enough torque to keep it in OD. Here is the deal. If im running 55-60 mph in OD when pulling and i press the gas a little when going over a hill it will shift down to 4th gear for more power. At 55-60 mph and having 3.55 gears my rpms run pretty low in OD and i have little power because im at the low range of the rpms. If im going 55-60 mph on a flat continuous surface, i have no problem with it switching back and forth. Im just worried im going to burn up my OD by it down shifting everytime i go up a hill but i didnt know if running my truck in 4th gear for an extended period of time running at 2250 to 2500 rpms would hurt anything. I know it recommends you disengage the OD when towing but i didnt know if the higher rpms would damage my motor.

shotgun

The issue is tranny temp and this is more a function of keeping the torque converter locked up rather than RPMs.

You can use OD if the transmission isn't shifting frequently (i.e., in Nebraska or Iowa with no head wind).

Ruprecht

I wish I knew more about gearing and transmissions to give an informed opinion here. My friends start talking about this stuff and my eyes roll back into my head. I just nod occasionally to be polite. I'm guessing even the experts sit around and argue about all the variables involved.
All I can do is say use your judgement and keep an eye on the condition of your oils. If you are burning up your trans or engine oil after only a few thousand miles then do something different. I keep a wipe of each oil on paper towel with date and conditions so I can compare over time.
You can also get fluid analysis done which can tell you alot about how things are running. Not sure about costs on that, but a friend told me he spent around $60 for one.

shotgun

If you're really concerned and tow a lot, buy a tuner/programmer that can display trans. temp.

ford4wd08

i have the same motor and gears and my truck shifts down when its on a hill when its not towing anything, but tn is pretty hilly and they get steap, so to answer your question that rpm range is fine wont hurt anything, i pulled a car hauler with a mustang on it back in november and left od on and my truck wasnt hunting for gears, i could control very well with my foot so i just left it alone, as stated above its more of a judgement thing