What is this 1?

[scooby5121]

2-32 page on my manual

For an allison or hydra 6 speed transmission , this position reduces vehicle speed without using the brakes. you can use it for major/severe downgrades and ..........

 

It is not what people on here think it was only used for!!!!!!!!!!!!!!!!!!!!!!!!

Scooby

 

Be in 6 gear and put it in and let it work !!!!!! your welcome and thank-you

!!!!!!!!!!!!

[scooby5121]

It's 1st gear, just takes the transmission control module and solenoids out of the loop by putting the manual shift valve into the 1st gear range.

not

[sdeeter19555]

Yeah, I never realized there was yet another notch below "M". If you pull it clear down into "1" at any speed, it really forces the truck to slow down by downshifting...even more so than manually downshifting shifting it seems.

 

I assume you use this for those times for when you have something like a heavy trailer and are descending a hill where its overrunning the speed limiting in T/H?? So you don't even have to use the brakes to get the trans to downshift?

[Portdriver]

So if I'm going downhill at like 45 mph in what ever gear I can shift into this and use the tranny to slow the truck? Its safe to do that? Not going to over rev the engine? Why don't one of yinz guys give it a try and let us know what happens? I ain't!

[MikeNH]

It's essentially impossible to over-rev a modern engine with an automatic. The trans won't downshift if it isn't safe.

[sdeeter19555]

I guess my whole question of this shift position is: when do you use it and why is it needed?

 

Seems redundant to have a manual position that you can force downshifts, and then to have one that does it for you??

[rotti]

I guess my whole question of this shift position is: when do you use it and why is it needed?

 

Tough 4WD road.....low range and quick pull to 1. Most engine braking, torque and slowest creep.

Pulling into my tight squeeze garage with the camper on and over the door hump.....want the most torque and slow creep.

Quick pull to 1.

 

I use it a lot.

Like I said before, it is quick short cut to your lowest gear.

[sdeeter19555]

So its just a bypass to get to first gear quicker than running through the manual button? I though it had something to do with normal driving and descending steep grades at highway speeds??

[rotti]

This is where 1st gear and low range would be indicated (assuming you have 4wd).

 

 

On steep highway grades I use tow/haul mode (read up on that) and let that auto do its thing.

It's not just for towing....great feature in the mountains to save your brakes. You could use M and pick your own gears but I found the tow/haul mode is smarter than me.

[sdeeter19555]

Ok, so its just a quick way to get and hold 1st gear.

 

Reading the description in the manual made it sound like it was used at highway speeds to slow down while descending a grade. I fully understand T/H, and use it quite a bit...and yes, the computer is smarter than I am....

[scooby5121]

I used it from 65 miles or 110 klms. an hour and dropped it in , no problem just when the traffic came to a sudden halt yesterday...

 

I use towhaul when pulling my camper thou.... haven't used it but will if I need the extra drag in a full stop.

[r1byker]

Ok, so its just a quick way to get and hold 1st gear.

 

Reading the description in the manual made it sound like it was used at highway speeds to slow down while descending a grade. I fully understand T/H, and use it quite a bit...and yes, the computer is smarter than I am....

No, read Rotti's post above yours. And the manual is correct; you can use it to maintain speed or slow down while descending a grade.

 

And it'll work in any gear. If you're in "D" and the truck is in fifth gear, when you move it to "M", the truck will still be in fifth gear and "5" will show on the display. Then you can shift down manually with the "-" button on the gear shift lever or, alternatively, shift up with the "+" button. I sometimes use it on twisty roads just to keep the tranny from shifting up and down.

[sdeeter19555]

No, read Rotti's post above yours. And the manual is correct; you can use it to maintain speed or slow down while descending a grade.

 

And it'll work in any gear. If you're in "D" and the truck is in fifth gear, when you move it to "M", the truck will still be in fifth gear and "5" will show on the display. Then you can shift down manually with the "-" button on the gear shift lever or, alternatively, shift up with the "+" button. I sometimes use it on twisty roads just to keep the tranny from shifting up and down.

 

 

For "M", yes...however, we are talking about "1" which is a notch below the "M"...There is shift positions for "D", "M", and "1".

 

The owner's manual reads that "1" is used for descending steep grades...like for compression braking at speed:

 

"When you shift to 1 (First) it provides the lowest gear appropriate to current road speed and continues to downshift as the vehicle slows, eventually downshifting to 1 (First) gear."

[txab]

Amazing at all the info you can learn about your vehicle just by reading the OM.

[r1byker]

For "M", yes...however, we are talking about "1" which is a notch below the "M"...There is shift positions for "D", "M", and "1".

 

The owner's manual reads that "1" is used for descending steep grades...like for compression braking at speed:

 

"When you shift to 1 (First) it provides the lowest gear appropriate to current road speed and continues to downshift as the vehicle slows, eventually downshifting to 1 (First) gear."

Ah, yes. Thank you. I wasn't looking that closely when I was driving a couple days ago and shifted into "M".