Downshifting without revving up the engine?

Exactly what you are trying to avoid.

 

I’m still trying to get my 12 speed auto to stop revving up when it’s downshifting.

 

How many years did you say you've been driving for now? And never knew that you don't have to go 1 gear down? With road ranger gear boxes you select the gear for the speed which is why both your method, and Ed's methods work if your only dropping one gear you may not have to rev up the engine as much if you've slowed down enough, the same with if your going from say 13 th gear down to 10 th gear if its going slow enough all you need to do is match the speed with the revs for that it would normally be doing in that gear, the key is to know what kind of speeds and revs match the gears, which after driving for 7 years in a manual you should have some idea of. Ever tried changing down gears up a 45 degree grade towing 192 tonnes? That will surely test out your gear changing skills in a real hurry which is exactly what happened to me the other day I'm usually fine on lesser grades where you may only change down a couple of gears however this hill really had us back down to almost crawl speed and one dare not miss a gear here. Starting off in 18 th down to 16th down to 14 th, 12 th 10 th as I jump two gears and finally in about 8th gear on an 18 speed road ranger I could continue to pull up the hill. When I'm changing down a lot of gears I will always leave the splitter on high and just drop the main gears that way if when I'm finally in the right gear if it just slows up that little bit more I still have the option of using the splitter gear to get that extra bit of power.

 

Let me know if you find out. When I was driving yesterday, I specifically paid attention to the transmission downshifting when I was slowing down. Sure enough, the ECU would raise the engine RPMs to shift into the next gear. The only time this didn't happen was when the truck went into coast mode and sat in neutral until I came to a complete stop. At which point, it would just pop into whatever starting it thought I needed.

 

Well everybody does that. This is not what the op was describing.

 

That must be what’s happening, forces the engine RPMs up, matching road speed. Floating gears requires bringing RPMs up first to match road speed. My knee hurts after watching Cattleman’s video. I think I’ll keep shifting the same way I always have. Interesting thread though.

 

You get peak torque @1100rpm on modern motors. It peaks at 11 and flat-lines all the way to 19.
We don't use hardwood crankshafts anymore.

We also need high EGT to keep the DPF clean. wasn't my idea....

 

One method is to keep your foot on the throttle when you downshift. Lets say you are on flat ground, or maybe you are slowing down to make a turn.
right before you downshift you adjust the throttle so you are "neutral" you are just maintaining your speed, almost coasting. There is not enough throttle that you can't easily pull the transmission out of gear, and you aren't speeding up. When you pull it out of gear your rpm won't increase much (you shouldn't hear a change) and the truck won't slow down much, but together they are enough to make a seamless shift. It is much easier to do at lower rpm.

It goes against all trucker "therory". It seems to be easier when changing from high range to low range so maybe a slightly slower shift to practice with. I mean, as fast as you can throw the lever across the tree...

 

I took a road test once. I asked if I could float the gears. Safety man says no problem. I had a habit of moving the gear shift side to side a few times in neutral between gears. Safety man asks why are you doing that? What? Oh!! I explain my last jobs Truck was old junk. Had to do that to make it shift right, or else it would get hung up in a gear. Just a habit, I guess. He says, well stop it, you don’t need to do that with our Trucks!! Lol. I still do it occasionally.

 

That takes all the fun out of downshifting with the jakes on!!