I was hoping one of you could help me. I've got a 1999 F-150 with the 4.6 litre and the manual tranny. It's geared with the 3.55 for what that's worth. Anyway, my wife and I just bought a very small camper trailer and I need some towing advice. 5th gear (overdrive) is out of the question for towing as I suspected and quickly confirmed. I can however, set the cruise at 65 in 4th and it will hold doing right at 2500 RPMs. It will also hold 70 in 4th, but at about 2900 RPMs. Do any of you happen to know at what RPM the truck has the most torque?

In case you haven't already figured it out, I'm a COMPLETE idiot by and large in terms of mechanical functions, so forgive me if I've used incorrect terminology in my attempt to get some advice. Any assistance you can offer would be much appreciated. Thanks in advance for any and all advice.

 

Your doing fine by holding 4th. Every engine has a different optimum Tq range, the 4.6 needs to be revved a little higher than other v-8's but still does a fine job. I have a 4.6 and tow often without problems. Really your RPM's in 4th are fine, much better than lugging the motor in 5th. You could change out your rear end gears to gain 5th gear back when pulling, but for the most part the expense isnt worth it

 

2500 is probably most comfortable for the drivetrain and your wallet (at 2900, you'll be able to watch the gas gauge move).

 

So it sounds like the 2500 RPMs range is about ideal in terms of efficient torque, speed and fuel efficiency?

 

The peak torque of the 4.6L is about 3500rpm, but it is happy in the 2200-4000rpm range. Fuel economy will start dropping off due to aero drag, not engine speed, the faster you tow.

 

I have a 4.6 and tow a 6000lb tt around 3500rpm and get almost the same fuel economy, i know it is hard to belive i still can't.

 

I've towed a small 5x8 enclosed trailer filled to the gills with the bed filled to the gills too, and I can hold as low as 55 in 5th on cruise control with 3.55's and a V-6..........

By the way, that tranny officially limits your towing to 3500 pounds. Any more than that is rough on the input shaft.

The 4.6 will rev all day. I wouldn't be afraid to run one at 4000 rpm continuously.

 

Well outside of your rpm issue, if your trailer has ST tires on it, which virtually every trailer has, the tires are rated for a maximum speed of 65 mph. So, if I were you, I would tow in 4th at no more than 65 mph. This is a safety recommendation more than rpm related.

 

You should be able to easily hold 65 in 5th on level ground.

 

You don't provide any specifics on your trailer so it is hard to advise. I'll say this. We had a 2001 5-speed with the V-6. We pulled a 2,000 pound tent trailer for thousands of miles using 5th gear with no problems whatsoever.

 

I used to haul a 6000 lbs boat with a v8 inboard engine with my v6 stick shift F150.. never a problem doing highway. I used to drop it in 5th at 65 and she'd pull fine.

Personally, feel free to down shift, that's what that stick is for!

The weakest point in the M5OD, is the input shaft, but if you take it easy when you release off the clutch, you will be good to go.