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I've seen the phrase "....I locked out 6th gear" and was wondering how this is done? The rough context this was said in was the owner was driving mountains/ hills with TC on truck. Truck was slowing down while in cruise ctrl. and maybe not holding the correct gear or not getting back to set speed. So he said he "locked out 6th gear" to better maintain his desired speed. (apologies as I can't remember the situation details completely) Truck was a 6 speed gas engine and newish, I think.
So I'm wondering what he means by this and whats he's doing? Is it something that can be selected from a cruise control menu or some other menu? (I know zero about whats in new trucks. The only digital computer display in my '98 is the second gen. Ipod.....)
Or is he doing something like putting the automatic trans into the "manual" mode the newer vehicles have, like my wifes Audi, that let you shift gears yourself and he's just not shifting any higher then 5th gear in his given situation, to maintain rpm's so not to lose speed on the hills?
Or some other magic method my limited knowledge can't guess at?
Thanks for the help. (apologies to the OP of the post I'm referencing, if on here. I couldn't find your post to ask you directly.)
“Locking our sixth” usually means setting the six-speed automatic transmission to keep it from up-shifting from fifth gear to sixth. Climbing a grade while carrying a heavy load and/or towing a trailer often requires downshifting to allow the engine to operate faster and generate more power and torque.
Normally this is accomplished with the transmission range selector set to “D” and then you use the +/- switch on the stalk to progressively lock out gears from the top down.
For example, you can toggle the “-“ button once to lock out sixth gear, or three times to lock out sixth, fifth, and then fourth. Once conditions return to normal, you can toggle the “+” button to restore the gears.
If you toggle “+” too many times, it will turn off the gear range display. You can turn the display back on with the “-“ button.
Topical discussion from the 2019 OM is attached below.
Thanks SD. Had no idea something like that existed. Glad to know it as I'll make use of it in the new truck for sure. I often miss these details due to pretty bad dyslexia, which is a real PITA, but I'm stuck with it.
Thanks you for your time and help.
I very seldom run in 6th when the camper is on the truck. The truck just spends too much time shifting between 5th and 6th. When we get out West and there are real mountains I often will lock out both 5th and 6th and sometimes will just drive in M instead of D. Just what you are comfortable with.
Thanks for the info.
Eye-balling the f350 LB, SC, DRW with the 7.3 or 6.2, 10 speed, 4.** rear. So I'm sure it's gonna be a pretty overwhelming switch from my '98 GMC 3/4, SRW. Choice also depends on if Mrs. wants to go with new camper too. Our current is pretty much had it's day and doesn't have swing-out brackets for DRW and I'm not comfortable taking it off when out camping for fear of jack failure. And Mrs. does always want to explore, as do I, when out camping.
Fantasy right now is the above truck, a 10.5' Northern Lite or Bigfoot and build a wood and corro steel sided "barn" to store the TC out of the weather. Climbing up on the TC roof time and again to assemble my PVC pipe frame, wrestle with draping over the tarp in the murphy's law wind that just happens to pick up right then, lace the whole thing down, replace the tarp every year due to holes from rubbing, fixing it after wind storms, not to mention it still gets rain, needles and sun damage regardless............ you get the picture.......
But dare to dream.........
I just put the truck in tow/haul mode and let it do it's thing. Never had an issue.
I can't recall if or what "mode" he had. I think I recall he found in cruise control it was searching too much. ( I realize cruise isn't tow mode)
Perhaps this will be less/improved with the 10 speed tranny.
Does "Tow/Haul" mode lock out gears automatically and adjust as needed?
Nice to see a BC'er here! Was just in Van for lithotripsy. Fun times!
There has historically been more variability in comments when Tow Haul is used with gassers on FTE. I really do like the way the braking works, however I find the upshift algorithm is too aggressive for my liking holding lower gears too darn long. I suspect that issue is much less apparent with diesels given the much higher torque.
I can't recall if or what "mode" he had. I think I recall he found in cruise control it was searching too much. ( I realize cruise isn't tow mode)
Perhaps this will be less/improved with the 10 speed tranny.
Does "Tow/Haul" mode lock out gears automatically and adjust as needed?
Nice to see a BC'er here! Was just in Van for lithotripsy. Fun times!
On our 2019 6.2 six-speed, Tow/Haul mode appears to make several adjustments to the transmission shift strategy. One is that it delays up-shifts when accelerating. Another is that it aggressively down-shifts when slowing down (engine braking). I haven’t observed that any gears are locked out.
I intensely dislike the downshift while slowing/braking behavior. Frankly, there have been times when I felt as if the truck was speeding up. As a result, I just don’t use the feature, as I find its behavior unnerving in our mountain-side neighborhood.
I do use the +/- shift switches, primarily to lock out upper gears to avoid gear hunting and low engine speed lugging. I really like how this feature works in our truck; I see it as a blend of automatic transmission convenience and manual transmission control.
I know a lot of folks just leave it in tow/haul, but as I recall they own diesels and seem to speak positively of it. I guess it makes sense that the same algorithm would not work as well with both gassers and diesels. I agree with your summation that the transmission in M is the way to go in the mountains and I also use it when our fifth wheel is on the back.
Thanks SD. Yes, it does sound like a blend of the advantage of manual with the convenience of auto.
Nice to have the two methods, tow/haul mode and the +/- switch, so you can pick what you like or what works for given situations.
"Locking out 6th"
