OK , heading out west and will be towing a 12000 lb fifth wheel thru the mountains. Never did mountain driving and this is my first ford truck. It has a tow package included. Hopefully some of you with experience can help me. Do I leave the truck in the auto tow/haul mode? or do I need to be using the 1 thru 3 lower gears? If so which gear to use and when? Thanks for your help.

 

whats the truck? specs plz

 

2008 F250 6.4L V8 Diesel, 5 spd auto trans, 3.73 ratio,

 

you should be fine in tow haul on the hills. going down you may wanna select a lower gear but the tow hauls should auto downshift for you on the hills. i dont know about those 3.73s youve got in there. i would get those out and 4.11s if you plan on towing that much weight alot.

 

Unlike some previous model years & other vehicle makes, it is a Tow/Haul selector not an Overdrive selector. As such, it would be a good thing to leave the transmission in tow/haul mode anytime you have the fifth wheel tagging along behind you. Your 2010 F-250 Owner Guide (starting right at/about page 285) has some very good input:

For the most part, just run in (D) with the Tow/Haul mode on for the uphill & flat sections. If you find yourself in a screwy position, where you are trying to start off from a dead stop on an uphill or with questionable traction, you may wish to downshift into a lower gear. This will give you much better control over the throttle & limits the amount of power going to the rear wheels.

On the downhill sections, let the motor do the majority of your braking! If you find that (D) is not providing enough braking, do not hesitate to get your load slowed down with the regular brakes & downshift a gear. If (3) is not cutting it, feel free to drop it down into (2). You are ultimately looking for that balance where the engine braking keeps your foot off of the brake almost entirely. On switchbacks, you may need to hit the brakes to go around the corners, but the engine braking should keep your speed in check to where you only need to brake lightly for a couple of seconds.

I have seen an amazing number of fifth wheel trailers & Super Duty/Heavy Duty trucks sitting on the side of the road with their brakes on fire/glowing/smoking because the owner relied on their brakes for the trip down a hard grade--between Colorado, Idaho, Montana, and Wyoming. Trust me when I say that you do not want to be that person!


Aside from that, enjoy the trip. I am sure that you'll be glad you took the drive!! Oh, and post pictures!!

 

Excellent advice Deluxe05. With regard to the 3.73 gears, you will be fine. Don't change them out. That was the factory spec gear for your truck and it's under warranty and you don't want to void it. The 3.73s will do fine with that weight. I have the 3.73s in mine and never have I wanted for a steeper gear. Ford is now making the 3.55s and 3.31s available in the 250s and 350s and the 3.55s have the same tow rating as the 3.73s.

With the torque the 6.4 produces, the 3.73 gears will serve you just fine.

 

changing the gears wont void the warrenty. you just have to have a reputable shop do it

 

Don't be too sure of that. Ford has denied warranties for a lot less. And as strict as they've gotten, they can and will deny a warranty claim if there's any way they can show a failure attributed to the part or parts that were installed aftermarket. 3.73s are fine in these trucks and with the poor mileage some 6.4 owners have been reporting, going to a steeper gear is going to impact fuel mileage with little benefit in pulling power. 12k is not going to cause a 6.4 truck with 3.73 gears to struggle.

 

Put it in Tow/Haul and roll out. I have noticed that my tranny will sometimes need me to brake for a second or two on a downhill slope to get it to downshift. The engine braking is awesome. It makes towing in the mountains easier since you dont have to find your own gear.

Back before I had a tow/haul button, I used to pay close attention to what gear I was in at the top of the hill and I would make sure I was in that gear or the next lower for the downhill grade. It is a good system, but is negated with the tow/haul.

FWIW, I towed my 5er from Alaska to Maryland and rarely shifted out of OD-tow/haul.

 

Thanks for the advice.

 

Excellent point, racinghoss!! The engine braking is so intuitive that I had completely forgotten that aspect.

TEA, think of it this way. If you just let off of the throttle, the truck will coast for a good bit. If you brake for a bit, you are sending the message to the computer(s) that you are intending on slowing down, and it will help you do just that.

 

Having driving in Colorado many times pulling various loads there is nothing to worry about. Use the tow/haul and go. No need to change gears for the trans or getting rid of the 373's they are fine.

You will see lots of runaway ramps for 18 wheelers on the big down hills but I have never ever been anywhere close to needing them. Just drive sensibly and you will be fine.

Going up hill just realize it is not a race. Let the trans drop a gear and keep your rpms around 2500 and then you will be fine to run it around 65 mph.

 

Excellent advice using the engine/tranny to keep your speed in check.

If you have to brake for a corner or switchback, do it firmly to get to a comfortable speed then let them cool. Don't ride the brakes for long continuous periods going into the corner.

 

For what it is worth, I don't have the newer truck, (mine is a 7.3 '99) but have learned a few things with my setup. When going down a long grade I use my brakes a few times to slow down if required before the curves. If I find myself entering a curve too fast I use the brakes and the brake controller manual lever to insure the 5th wheel (36 ft) does not push me too hard in the curve. If the trailer starts to fish tail going downhill I use the brake controller to keep it BACK there. I have a Prodigy controller that displays the amount of braking being applied and has different basic settings for normal braking. The controller should be installed within easy reach of manual brake lever because it does require to take one hand off the steering wheel. With a little practice you will know the right amount of brake to apply if needed. It is a good idea to remember to use the same gear going down a 6% as it took to go up.
Your transmission will work just as hard going downhill as it does going up. For that reason you should have a transmission temperature gauge to monitor the temperature.

 

A lot of good advice here. I will just say do not ride your brakes. They will heat up and get soft. What I do is slow down 5-10 mph less than the speed I want to go and then let off the brakes to let them cool when the truck comes back up to speed. When I was young and stupid I rode my brakes going down a steep grade and lost my brakes. The only thing that saved me was having a manual trans and jamming it down to a lower gear.