I understand the modular engines are OHC and and are more tolerable of high RPM operation. Plus, the 4.6 is a square bore*stroke, so it isn't like it is designed as a stroker.

That said, I have a question.

My neighbor has a company provided 2004 F150 with a 4.6. He and I were working on his truck putting in a new headlight bulb when he mentioned he runs his truck all the time with the OD off. Apparently even on the highway. He has a bed full of tools and stuff. I'd estimate that there is maybe 1000 pounds of tools, maybe a bit more. I don't know what gears he has but he says 65MPH is around 2700RPM.

He has around 134,000 miles on the truck and no major mechanical issues yet. I went for a spin with him and, from inside the cab, you'd never know it was spinning that high. He told me his old truck was a 3 speed and didn't have an OD at all and ran like this one, except the new one handles it better.

He told me his mileage was around 14-15 overall. I would have expected a lot worse. I know more RPMs doesn't necessarily translate into more fuel usage, but we're talking 800RPM more, all the time.

I don't know much about automatic transmissions but I do know he's running 1:1 without OD. Is there an advantage or disadvantage to that? He does get some engine braking that isn't there in OD. I'm pretty sure the torque converter locks in 3rd.

So I guess my question is has this guy been incredibly lucky or does this sound okay for him?

I've read a lot for the "OD off" threads here. Those threads are about people turning the OD off around the city. This is a guy who has OD off all the time. Weird!

 

wow thats like 4.33 gear

 

Well given the conditions under which he has the truck, there is no real harm in it.
He gets more throttle response to carry the weight.
Towing or weight in the box may demand not running in OD. Makes little difference.
He may be a bit missguided on relying on a fact that the old truck was only 3 speed and compairing the new to the old from just that point alone.

Aside from those possible notions, I suspect the real reason is,
He is not paying for the gas,oil changes, the wear is not his problem, the major repairs may not be his problem either etc.
I might run the truck for the best feel to me too if those were the cases without requard to who owns the truck.
Company owned or leased trucks are often driven into the ground in short order by many who use the same truck, so an ownership attitude is just not a factor.
Faster it wears beyond reliability the faster he gets a new truck.

 

Bluegrass-

Good point, I didn't even think of that. I bet they take care of everything. The fact it has survived this long makes the engine look good, assuming it hasn't had any major repairs. I'll ask him next time I see him. I think he got the truck when it was a year old so not all of those 130k+ miles were OD-free. I also don't know his ratio of city to highway. I do know the engine runs strong and fires up right quick.

I tried some crazy math and I think that if you use 3rd as your top gear your axle ratio is an effective 5.07 or something close.

3.55 * 1.43 = 5.07

3.55 - just guessing
1.43 - reciprocal of .7, which is gear reduction from third to OD

 

I don't know about your math but 3rd gear is 1 to 1 making the effective gear whatever the rear ratio is.
If the trans is a 4r70w, the OD ratio is .77.
This make the final ratio in OD assuming a 3.55 x .77 = 2.73 all rounded numbers used, for 4th gear.
Quite a difference in pulling power between 3.55 and 2.73..
OD puts the engine so far down in it's torque band that there is almost no throttle response until the road speed gets up over 65 mph.
The 2 valve 4.6L torque peak is up over 3200 rpm so the normal cruise speed in mph puts good torque, way under that peak.

 

Aren't bigger numbers lower?

If so, then 3rd gear has to be higher (bigger) than OD.

You'll admit that 4.56 is lower than 3.08, right?

Edit: NM, I think I understand what you are saying. Hmm…

 

Using my transmission:

Model: 4R75E with 3.55:1 LS differential

1st 2.84:1 » 10.08:1
2nd 1.55:1 » 5.50:1
3rd 1.00:1 » 3.55:1
4th 0.70:1 » 2.49:1

Reverse 2.32:1 » 8.24:1

Is this correct?

Edit: A spreadsheet of various combos. Possibly using faulty logic.