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Heavy Towing in 5th Gear (68RFE)

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Old 01-30-2018, 12:12 PM   #1
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Heavy Towing in 5th Gear (68RFE)

I recently swapped the factory 17" wheels and 265/70/17 tires for a set of 18" wheels and 285/70/18 tires. This obviously resulted in drop in RPM at any given cruising speed, and unfortunately pulled me right out of the sweet spot for towing at 62-65mph, and now the truck lugs a little bit (below 1500RPM).

So, here is the stupid question for today: Is there any issue with "locking" it into 5th gear to bring the RPM up? My Mini-Maxx shows the torque converter apparently locks in 5th, so in my pea brain everything should be just fine? We are planning a pretty long road trip this summer and will be at (OK, maybe even slightly above ) rated capacity, and I am trying to decide if I need to look into a gear swap, or if I can just use the fancy buttons and ***** already present in the truck
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Old 01-30-2018, 04:48 PM   #2
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That is where i Run Mine. Just spent 5 Months in the Canadian Rockies and it worked better for me. Truck looses too much speed before it decides to downshift from 6th otherwise. Rock Steady running 5th.
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Old 01-30-2018, 04:58 PM   #3
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Towing in extreme headwinds I often lock in 5th on my 68RFE just to keep the EGT's reasonable, fuel burn is not nice though. When towing in the mountains I always manually shift down that way the engine is not lugging.
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Old 01-31-2018, 06:19 PM   #4
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That’s the beauty of the newer autos, you have six gears and can lock in the gear that suits conditions like a manual. Run what you like.
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Old 02-02-2018, 01:07 AM   #5
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I tow our 15k fiver in fifth gear about 90% of the time. I will occasionally shift to sixth on the flats with no wind. My deciding factor is EGTs. With 3.73's and the 68RFE, I turn about 1900 rpm's at 65 mph.
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Old 02-02-2018, 08:07 PM   #6
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I tow our 15k fiver in fifth gear about 90% of the time. I will occasionally shift to sixth on the flats with no wind. My deciding factor is EGTs. With 3.73's and the 68RFE, I turn about 1900 rpm's at 65 mph.
That's right where mine is as well. I hitched up and went for a little test run this afternoon just for grins and to play with the "manual" transmission mode. Worked great!

As always, thanks for the feedback everyone!!
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Old 02-12-2018, 02:50 PM   #7
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I tow 130000 lbs and always tow in 5th..I too have 18 inch tires...at 65-70 mph I am at usually 2000-2100.....been that way for the past 2 trucks. That is the sweet spot for it and it purrs up and down grades and never skips a beat....It takes a pretty steep grade or a really long grade for it to drop down a gear...
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Old 02-14-2018, 07:39 PM   #8
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I keep reading about the weak,overdrive gear in the 68 RFE. Is that just sixth gear or also fifth ? Craig
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Old 02-14-2018, 07:48 PM   #9
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My biggest issue is in 6th it hunts gears even on the littlest grades. I 5th it just purrs along......Your rpm's need to stay above 18-1900 to stay in your power band.... On flat ground in 6th mine drop to 13-1400...
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Old 02-14-2018, 08:20 PM   #10
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I agree with keeping the RPMs up. My 03 really likes 2100 to 2200 . My 12 is waiting for me to return from Arizona so I can swap the beds on my trucks and then I will be able to drive it again but I'm glad to hear that the 6.7 likes higher rpm's too so I can avoid using sixth gear so much . Craig
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Old 02-14-2018, 08:47 PM   #11
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Originally Posted by steelpony5555 View Post
I tow 130000 lbs and always tow in 5th..I too have 18 inch tires...at 65-70 mph I am at usually 2000-2100.....been that way for the past 2 trucks. That is the sweet spot for it and it purrs up and down grades and never skips a beat....It takes a pretty steep grade or a really long grade for it to drop down a gear...
Wow!! You tow a 130,000 trailer?? What's ya pulling? A jumbo jet?

I knew these trucks were better than any Ford, GM, or other truck manufacturer, but that exceeds any expectations I ever had!!!




Lol
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