Drive vs setting transmission to 5th for pulling?

[632sub]

Is it better to pull my 13,500lb 5th wheel in drive or manually putting it into 5th.(2012 crew,4/4,6.7, 68rfe)

 

[Cummins12V98]

Should pull just fine in 6th.

 

[Bob4x4]

With the very tall gearing some of these trucks are coming with,under a heavy load 5th may give you better mpg

 

[Cummins12V98]

With the very tall gearing some of these trucks are coming with,under a heavy load 5th may give you better mpg

I found I got slightly better mileage in 5th with 3:42's in my 11 RAM Dually. The was towing a combined load of 29K.

 

[RVTRKN]

The 3:42 is to low for the Cummins 6.7 despite what Dodge claims. I would tow in 5th heavy with the 68rfe and the G56 as well as the Aisin. 5th and 6th are overdrives and should be downshifted under heavy loads. I do run in 6th with my G56 and 3:73 until I start a uphill run and allways while climbing a steep grade regardless of ease. 6th is overdrive in the G56 but the auto options no mater which version have 5th and 6th as overdrive's. Your doing the right thing, and as noted, you'll get better milage and save your trans.

 

[orhusky]

We have 4:10's and leave it in D and let the truck decide until we get to the grades. (I tend to down shift at the bottom of the grade and "walk" the load up a hill in 5th or 4 depending on the incline and length of the grade.) I have done some very informal testing on a long flat road and the best fuel mileage was in 6th at about 60 mph at 1700 rpm.

 

[RustyJC]

Until we get into the hills where downshifts to 5th become too frequent, when we're towing our 5th wheel I will engage tow/haul, the exhaust brake, put it in Drive, run it up to 65 MPH on the Interstate and set the cruise control. With 4.10 gears, this puts us at about 1750 RPM, and the truck seems quite happy there. If we get into hilly terrain where it wants to downshift to 5th on the upgrades, I'll switch off cruise control and drive it myself, letting the speed bleed off a little on the upgrades to keep it in 6th. Seldom do I have to manually shift it down to 5th (or lower), and that's generally on steep terrain with lots of curves.

Rusty

 

[TJJEEPER]

I tow in Drive with my signature truck. From the "lie-o-meter" the mileage has always dropped when I go to 5th. I'll even purposely speed up and back off to get the 6th gear shift and let 'er pull. Best guess is between 24 and 25,000 lbs with the 5er on the pin.

 

[Bug Out]

If you have 3:42's like I have, 5th gear 60 mph and under.... Flat I-70 Kansas stuff, or 65MPH and above, 6th is great. 4:10's, 6th gear, let the transmission shift.

 

[Mawvelous]

If I am not mistaken the 13's & later SRW's come W/3:42 ratio. Earlier trucks 3:73 or lower were more common.