tow/haul

[porthole]

Tow /haul offers two different and distinct advantages when towing.

First it will raise the up shift and down shift points to better leverage all that torque you have available.

Second, most systems lock the torque converter from 2nd gear up. This allows all that torque to be used instead of some of it wasted through the torque converter slipping (not really slipping, as it is a fluid drive)

The locked converter aids in decel as the drive shaft is "locked" to the crankshaft through the trans. This allows what little natural engine braking is available to work, and if you have an exhaust brake of some sort T/H allows it work much more efficiently.

 

[beasleyrl]

The toy hauler with three axels and with water 110 gallons and fuel for generator is pretty heavy but everyone on the list is getting far better mileage than I am.
I have a Ford F-450 and it is geared rather low but pulls really well.

I hate to admit it, but I've had a Dodge 2500, Chevy Silverado 3500, and now a Ford F-450 over the last 5 years or so. Like you, my F-450 is geared low (4.88). On all of the other trucks, I needed the tow haul -- especially in the mountains going downhill or simply trying to stop the rig. However, with this Ford, it doesn't seem to make a lot of difference unless it is a very steep downgrade road.

As for MPG, this truck is by far the worst of the 3. At 65MPH or slightly more, pulling the 18K pound Cyclone, we get about 6.5MPG. At 60, it averages almost 8MPG. With this configuration, speed definitely makes a difference. Unloaded running through the mountains at 70, the truck gets about 15MPG. With that said, pulling this Cyclone, it is worth every extra gallon of fuel we use. I certainly can't say you don't know that 41 foot trailer is back there, but it pulls it well and stops it with little effort!

 

[porthole]

Roger, you can still benefit with the tow haul - locking the converter.

 

[bikerbob]

Hey TeJay, Thks. for replying.Having not camped in my new TT yet, all i can say is i know is Connie n I are gonna Luv. it. It is always an adventure with these things TT There is so much to learn about ur TT. The layout is Great because the bathroom is away from the bedroom and close to the door. The TV swivels so u can move it any direction u need. When u pick-up your TT on the walk thru ask plenty of Questions... Make sure everything works..They said here is the TV and tried to move on ...but i said lets see it work? Well it didn't so after about an hour and 2 more techs tracing wires n power chasing they got it working.. so a 1 hour walk-thru lasted 3 ..Make sure u find out where the Fuse is for the Weather Radio as this will come on at any time on outside speakers n drive the neighbors nuts...LOL Be ready to buy a mattress too... As for towing it u should have no problems with a new truck. Hope u enjoy ur New 24 RBS .. I see we are Junior Members, do you know what a junior member is? Take Care>>>Later>>>

 

[TXBobcat]

Took my 2006 F250 in to the dealer for some maintaince and tuneup. While visiting with my service manager (known him for many years) I asked to talk to the transmission man. I asked him when I should be using the Tow/Haul feature. He told me "Anytime I am towing my trailer". It helps keep the transmission cooler because it pushes more fluid and keeps the engine in a higher RPM.

My truck has a 3.73 rear end and I get fairly good mileage. I have a 45gal tank in the bed and the 38gal OEM tank so I normally have plenty of fuel.
As was told me when the fuel prices were very high, "If you can't afford the diesel, Park it". At times when pulling in hilly country like I did around New England states I got around 8 or 9 mpg, but the TV did a good job pulling the hills.

BC

 

[lwmcguir]

Tow /haul offers two different and distinct advantages when towing.

First it will raise the up shift and down shift points to better leverage all that torque you have available.

Second, most systems lock the torque converter from 2nd gear up. This allows all that torque to be used instead of some of it wasted through the torque converter slipping (not really slipping, as it is a fluid drive)

The locked converter aids in decel as the drive shaft is "locked" to the crankshaft through the trans. This allows what little natural engine braking is available to work, and if you have an exhaust brake of some sort T/H allows it work much more efficiently.

I think adjusting the shift point RPM up-wards is the most important thing. The only Diesels we have had in the past 50 years that you could truly lug without hurting them were Mack's and John Deere. Even then if you get below 1500 rpm on the JD and 1200 on the Mack trucks you were shortening you engine life. We like to run them well over 10,000 hours so it was a big deal. Always use T/H when towing.

 

[trdeal]

We have an 2007 F-350 and I always use T/H when towing,unless the road is wet.The manual recommends that you do not use T/H when the road is wet because of possible loss of traction during deceleration.I have the 4x4 with the 4:10 rear end and get around 10-12 mpg when towing.

 

[porthole]

I think adjusting the shift point RPM up-wards is the most important thing. The only Diesels we have had in the past 50 years that you could truly lug without hurting them were Mack's and John Deere. Even then if you get below 1500 rpm on the JD and 1200 on the Mack trucks you were shortening you engine life. We like to run them well over 10,000 hours so it was a big deal. Always use T/H when towing.

HD diesels are not the same as light duty diesels. HD diesels are designed to run a continuous load at about 80% engine capacity.Properly maintained 5-10,000 hours or more can be expected.

The trucks we are talking about are light duty.
You can't lug a diesel with an automatic trans.

The newest power ratings for the Ford 6.7 have that 800 ft lbs of torque coming on just over 900 rpm.

I'm sticking with the torque converter lock up being the most important T/H programming change.

You can manually change the shift points (to a degree) but the TC lock up is out of our hands.

TC lockup lets the engine use the torque to move. Also allow engine braking to be more effective, especially when combined with an exhaust or turbo brake (yes I know diesels inherently have almost no engine braking).

By locking the TC the trans temp is kept lower as there is no extra heat being caused by TC slippage (fluid, not clutch).

If your truck is equipped with an exhaust brake, the T/H mode by raising the shift points and locking the converter actually let the brake do some work.

The rpm's need to be high and the converter locked for the brake to be effective.

Most T/H modes will also allow some line pressure increase, helps to keep the clutches from slipping under all that torque.

 

[lwmcguir]

HD diesels are not the same as light duty diesels. HD diesels are designed to run a continuous load at about 80% engine capacity.Properly maintained 5-10,000 hours or more can be expected.

The trucks we are talking about are light duty.
You can't lug a diesel with an automatic trans.

The newest power ratings for the Ford 6.7 have that 800 ft lbs of torque coming on just over 900 rpm.

I'm sticking with the torque converter lock up being the most important T/H programming change.

You can manually change the shift points (to a degree) but the TC lock up is out of our hands.

TC lockup lets the engine use the torque to move. Also allow engine braking to be more effective, especially when combined with an exhaust or turbo brake (yes I know diesels inherently have almost no engine braking).

By locking the TC the trans temp is kept lower as there is no extra heat being caused by TC slippage (fluid, not clutch).

If your truck is equipped with an exhaust brake, the T/H mode by raising the shift points and locking the converter actually let the brake do some work.

The rpm's need to be high and the converter locked for the brake to be effective.

Most T/H modes will also allow some line pressure increase, helps to keep the clutches from slipping under all that torque.

We almost agree on this. The engine does operate a higher rpm longer befor shifting and locking, which was my point. I have had diesels for over 50 years so have seen a lot of things come and go. The computer and the T/H is great and on that we agree. It was designed and engineered to get the maximum safe performance out of the engine/transmisson that can be had.

Our HD units do run typically at nearly full load or in the case of the trucks when you have a heavy load on a challenging road.

Where we disagree is the luggging, you are right that you cant kill the engine down with an automatic, however if you have a heavy load and dont use the T/H you will shift and lock up quicker and lug the engine. Not kill it.

Been there and done that for sure in the old days.

 

[lwmcguir]

Fords do lock up the torque converter without being in the T/H setting if someone thinks they don't. The new Ford 6 speed has two overdrives. Don't know how the Allison locks up.

 

[lmcclure]

We use T?H whenever we are hooked up.

 

[porthole]

Fords do lock up the torque converter without being in the T/H setting if someone thinks they don't. The new Ford 6 speed has two overdrives. Don't know how the Allison locks up.

All modern light duty trucks and cars use lock up converters. Most do not lock until in high gear.
The new Ford and Allison are similar, each being in overdirve in 5th and 6th gear
GM
Ratios: 3.100 - 1.810 - 1.410 - 1.000 - 0.710 - 0.610
Ford
Ratios: 3.970 - 2.320 - 1.520 - 1.150 - 0.860 - 0.670

Both trans' can lock the converter in 5th or 6th

In similar trucks, F-350, GMC 3500, 373 axle rations, almost the same tires, the Ford is about 200 rpm more at 65 then the GMC.

T/H mode with the GM locks the converter in 2nd through 6th, that's the advantage. I think Ford does the same but not positive about 2nd gear.

Where we disagree is the luggging, .............. however if you have a heavy load and dont use the T/H you will shift and lock up quicker and lug the engine. Not kill it.

Not going to happen with the modern "automotive" diesels. The computer control will do everything necessary to keep the engine from getting hurt. Satryting with de-fueling the engine. And with the new ford, taking the throttle away.

Been there and done that for sure in the old days.

I think we both can agrees we ain't talking 'bout 6-71's 904's 3208's Maxidyne's, JD's Luggers (you left that one out)

 

[lynnmarti]

I use tow/haul any time I'm towing. 11-13 mpg depending on terrain/wind/speed etc. I try to stay around 60-63 mph. 2008 Dodge 3500/6.7L diesel/Bighorn 3400RL.

 

[caissiel]

My Tow / Haul mode is in the right hand and was in the ears. But now my engine is so quiet that I use the RPM gauge. Ah. Ah. Ah.

 

[hoefler]

Dodge only locks in high gear when not using tow/haul. The exhaust brake only works in high gear as well if you are not using tow/haul. In tow/haul, locks in every gear except first, exhaust brake will work all the way down to 15 mph in second gear. I am down here in the Ozark Mountains 30 mies west of Branson. I run tow/haul 100% of the time it is running, towing or not, keeps it from shifting as much and helps with braking in the hills and curves. Fuel mileage is better also.