what gear to tow in????

[skorski]

2014,3500,4x4,aisin trans 6 speed. Taking off end of Dec. towing a 13,000 fith. Should I keep it in D or lower it and lock out OD? I know the ex.brake works better locked out. But I want the best fuel econ and best for the truck. My first 3,000 mi trip with new truck, only got 6,000 on now going to Az. for winter.

 

[RustyJC]

With a 4.10 axle ratio, when towing our much heavier 5th wheel I just turn on the exhaust brake, turn on tow/haul, run it up to 65 MPH, set the cruise control and let the computers handle the gear selection. The only exception is if we get into the hills where the cruise control may force downshifts by trying to hold the speed setting - in that case, I'll shut off the cruise and handle the throttle with my right foot, letting the speed degrade slightly to avoid an unnecessary downshift or, if it's hunting too much, just lock it down into 5th for awhile. In most conditions, though, the truck is quite happy in 6th at 1750 RPM @ 65 MPH. The truck will let you know if it's unhappy - if it isn't, I'd let it do its thing; the engineers spent a lot of time setting it up to do just that.

Rusty

 

[SnoKing]

With 3:42 gears(SRW) you will be coming out of 6th more than Rusty! SNOKING

 

[Dieselnerd]

You don't say what rear axle gear ratio you have. If it's a SRW with 3:42, you may be happier with 5th gear. I also have a 4:10 and like Rusty does, I just put it in tow/haul, Drive, exhaust brake on and let it roll. Mine rarely downshifts out of 6th and I have a heavier trailer than the OP.

I'm also heading to AZ for the winter. Mine even stays in 6th on that long hill on I-10 with the rest area on the crest of the hill before you get to Benson.

 

[NC Hauler]

With a 4.10 axle ratio, when towing our much heavier 5th wheel I just turn on the exhaust brake, turn on tow/haul, run it up to 65 MPH, set the cruise control and let the computers handle the gear selection. The only exception is if we get into the hills where the cruise control may force downshifts by trying to hold the speed setting - in that case, I'll shut off the cruise and handle the throttle with my right foot, letting the speed degrade slightly to avoid an unnecessary downshift or, if it's hunting too much, just lock it down into 5th for awhile. In most conditions, though, the truck is quite happy in 6th at 1750 RPM @ 65 MPH. The truck will let you know if it's unhappy - if it isn't, I'd let it do its thing; the engineers spent a lot of time setting it up to do just that.

Rusty

Same here, I tow in the mountains of WV, TN, NC, SC and VA..quite a few of those are quite steep, curvy, mountainous secondary roads...but I put truck in T/H with EB on and let the truck downshift when it needs to...25,000 miles on the truck and never an issue, when on the Interstates I travel, all in the mountains, I can put in cruise control, ( which I really couldn't do on last Ram and all Chevy D/A's I had due to a lot of downshifting), set it on 65 and it works like a dream...really pleased with this truck towing my 5er loaded to 16,200#.

 

[Too Tall]

2014,3500,4x4,aisin trans 6 speed. Taking off end of Dec. towing a 13,000 fith. Should I keep it in D or lower it and lock out OD? I know the ex.brake works better locked out. But I want the best fuel econ and best for the truck. My first 3,000 mi trip with new truck, only got 6,000 on now going to Az. for winter.

I don't use D while towing. I use the selector and choose a gear that will allow me to go up mild hills, overpasses, etc... without downshifting. If that is 6th, great, stay there. Save your transmission and engine by preventing frequent downshifting.

For my 2500 with 20" wheels (3.42), 5th gear is where I live most of the time. (always use tow mode). It's rare that I can keep it in 6th without constant downshift. But there are times when I get a good tailwind and flat land, I can keep it in 6th and get great mpg. But it's rare. If I had a 3.73 or 4.10, I could probably stay in 6th with my little small RV and probably pick up 1 mpg.

 

[Brocky]

I have 3.73 rears and gross 23,000# with 32 ft gooseneck enclosed car trailer. As the EB is always on I just put in in TH and D, set the cruise about 68 and let her go. From Greenville SC to Winchester VA and back got 11 MPG. The only time I locked it in 5th was coming down Fancy Gap on I-77

 

[skorski]

Thanks for the info I have 373 gears Think I will just put it into drive and play it by ear.

 

[Stab]

Whatever gear the engine is @ it's peak torque, is what gear you need to be in while towing. It's really that simple.

Crusing without a load is a total different animal.

 

[gsbrockman]

The only time I locked it in 5th was coming down Fancy Gap on I-77

Gotta love that section of I-77 for sure....traveled it many a time. Love the Big Walker Mountain Tunnel and East River Mountain Tunnel on I-77, too.

 

[Cummins12V98]

With 3:73's and only 13K you will rarely down shift unless you are in some serious mountains. Leave it in 6th and enjoy the ride!

 

[TDickerson]

I have the 3.42 gears and find that pulling my 8K TT, I am usually always in 5th gear. Any slight grade will downshift from 6th to 5th. Although, this is with cruise control on. With it off, I can control it better and not always shift out of 6th, but that will usually slow me down. I have experimented with this and find that the fuel economy is hardly any different running 5th vs 6th when towing. 5th gear is the way to go when towing and in cruise. Otherwise, you will be shifting often. The other gears seem to be different, but why sacrifice fuel economy when not towing just to stay in 6th gear that really doesn't give you any better fuel mileage when towing. Just my opinion.

 

[seafish]

Whatever gear the engine is @ it's peak torque, is what gear you need to be in while towing. It's really that simple.

Crusing without a load is a total different animal.

THIS is the correct answer…maintain rpms at peak HP, between 1800 and 2200 at any speed and any grade while loaded. Cruising level and unloaded you can readily drop to 1500 rpm.

The tachometer is your friend, though an EGT pyrometer is also useful if towing a lot.

 

[Brocky]

Seafish

It is not all HP!! It takes Torque also. The sweet spot for any engine is where the Horse power and Torque curves cross on the graph!! Gear your truck to cruise at your desired speed just above that point so it will drop into the sweet spot as soon as you hit any gradiant...