I will be pulling my 32' TT that comes in at about 8K lbs. My Ex is a stock 05 6.0 with 285 tires. Should I be putting it in tow mode and forgeting it? Tow mode seems to hold it in a lower gear on the highway regardless of the load. I would think this would decrease fuel mileage. Should I put it in tow mode until I am rolling down the freeway at a steady speed and then turn it off as long as it is not hunting?

Also I noticed the sticker on my hitch says 12,500 for a max, but I have never read the Ex being rated that high.

 

I've got a stock 6.0 and I tow 34' TT only on steep downgrades I'll turn of OD other than than I don't worry about it I drive quite a few hills through ky, tn, and nc

 

So you just drive without tow mode on?

 

Drive in the mode you like best. The truck was designed to tow either way. If you like the way it behaves in tow, use it. If not, don't use it.

I think you'll find it very helpful if you are on grades. It doesn't do much for you on level roads.

 

Thanks for the info. Judging by your signature it looks like you should know!

 

tow mode changes a variety of parameters. A forum user either here on the 6.0 forum that knows a lot more about the 5r posted up most of them a while ago. Apparently in addition to changing the shift patterns, it also changes line pressure, slip at the torque converter, and affects the variable vanes of the turbo to provide maximum torque and engine braking, and it does so in conjunction with the coast clutch on the transmission.

The tow/haul will not keep your truck out of overdrive on the highway, for some reason that is a common misconception. I drive with mine engaged while towing and do most of my driving in overdrive on the interstate. Basically, though, on the power side, it will let you throttle up higher at idle, it will hold each gear for longer, it will shift harder (which protects the transmission), it will allow you to give more throttle in each gear before downshifting, and it will hold downshifts until you pull the hill. On the braking side, it will give you maximum engine braking by using the vanes of the turbo and the coast clutch, which means on hills you don't have to touch the brakes except to knock it down a gear if it starts to gain speed, and in stop and go traffic instead of driving with your left foot on the brake, you just lift the throttle and the truck instantly starts to retard its speed, without touching the brakes. Its so nice that I use it in stop and go traffic even when I'm not towing. But really, until you tow something heavy you won't fully appreciate it. Run with it and run without it, it makes a big difference in towing, especially if you don't have much experience towing heavy things.

 

Very cool. Which gives best mileage towing on flat ground?

 

I programmed the tow/haul mode when I worked on this transmission at Ford. There is nobody out there posting that knows more about this than I do.

What you have posted is a common misconception. It does NOT change line pressure, torque converter slip, or how much torque the engine produces.

It does change the setting on the turbo vanes to provide engine braking, and it does change the shift pattern. It will still use OD at highway speeds.

Depends on the speed. Below about 60 MPH tow/haul off will have better fuel economy because it will be in overdrive. Above about 60 MPH it will make no difference because the trans will be in overdrive no matter which mode you select.

 

can you tell me why my truck idles up about 300-500 rpm higher before starting to apply it towards forward movement with tow haul on than with it off? It also seems like it changes lock up characteristics on the interstate... I've noticed, for instance, that with cruise control at around 65 mph with tow haul off my rpm's might be up around 1850 rpm or whatever, and if I hit tow haul on, they will drop maybe 50-100 rpms. Its visible on the tach and audible in the engine note.

 

Kovalsky and friends did a great job on this transmission. This tranny is one of the best reasons to buy a 6.0L over a 7.3L.

On our rig, I put in Tow/Haul mode, accelerate to my desired cruise speed (68 mph), then put it on cruise. My rig will hold this speed on almost all interstates. This reduces stress levels a lot.

When in the mountains, the Tow/Haul mode is essential to help control downhill speeds without heating up the service brakes too much.

 

No, I can't explain any of that.

When the truck is just starting to move it does not matter if tow/haul is on or off. The only things in play are how much torque the engine is making, what RPM the engine is at, and the hydrodynamic characteristics of the torque converter. Tow/haul doesn't modify any of those.

I can't think of any reason that turning tow/haul on at 65 MPH would make the engine speed go down. I don't understand why that would happen. I never saw it happen.

 

Truck towed camper to the camp site very well. Used tow mode the whole way. I do have a question.

My fan would cycle on occasionally even on the highway. Is that normal?

 

Yes, the ecu will dial up the fan as needed. When I towed my first 7k load out a hilly interstate, I was concerned when my was coming on as well. I bought a scangaugeII to monitor actual oil and water temp. It is considered a necessity on a 6.0 to monitor the difference between the two, and now I find that I don't hear the fan as much, because when I see temps rising I can take it easy and keep them down. I don't know how much experience you have towing, but you aren't going to be able to tow a 10k trailer up a 7%, 3 mile hill at 70 mph without really getting everything hot as hades. Yes, a stock 6.0 will easily pull that load at that speed up that grade, but youre far more likely to heat everything up, risk lifting a head and blowing a headgasket, melting a standpipe, cracking an EGR cooler, blowing an IC hose, or venting coolant out the degas bottle. The stock truck is supposed to start pulling fuel I think at like 240 degrees, but put a scangauge on there and let it get to 240 and if its pulling fuel its not pulling much. basically it will let you keep rolling coal up that mountain till you have plastic in the block and coolant puking everywhere and a $7000 repair bill.

You have got to keep an eye on the temps on these trucks.... if its getting too hot, you may need to slow it down and tuck in the right lane for the rest of the climb. If temps keep rising, pull over and give it a break. Check coolant levels and fan operation while youre resting.

the powerstrokes are great motors but the have a "hot" tune from the factory compared to the commercial series of engines from international, and they will heat up if you let them. But this isn't necessarily a 6.0 problem. The same is true for any engine, be a 6.8 v10 or a 5.9 cummins, they will all overheat when too much is asked from them, and all will eventually melt down if driven too hard.

 

Sounds like a great way to "exercise" the unison rings and turbo vanes for those of us who don't put tons of mileage on the 6.0. (Thinking of ways to keep my unison ring from sticking again....)

 

don't some of the later 6.0's have a tune in the ecu to cycle those at engine start up and shutoff or something? I wonder if you could get a flash to have yours do that, if its proving a problem.