Downshift help

It was meant to be a estimate. Thanks for confirming. That truck should run out well if its ungoverned.

 

What my instructor taught me (and it worked pretty good with the truck I was testing in) was to simply bring it down to around 1000 RPM. Clutch, neutral, snap the throttle quickly to the floor and release. While you're releasing the throttle, push the clutch back in just enough to break torque (maybe 2-3") and hit the lower gear.

Now add in a down grade. Same procedure as before except bring RPMS down lower to around 800ish. Snap the throttle but hold it there a little bit longer to bring the RPMS up higher to compensate for gravity speeding the truck up. On an upgrade, downshift with the RPMS up a bit higher (because gravity will slow the truck down faster) and give it less fuel. I find floating much easier and smoother though personally.

 

Ugh... I could never understand double clutching. It's such a savage way of operating the equipment.

Finesse through floating is so much easier on the components when done correctly. But there's the problem... not everyone can learn or teach how to do it correctly.

 

Honestly I found floating wasn't all that bad to learn. I guess all those days I skipped school to go ride in the logging truck paid off lol.

 

I think I might have used this metaphor before, but when I was taught floating by someone that knew how to teach it, it was like the skies opening and a choir singing. Granted, I'm not perfect and have an off-shifting day every once in a while, but when you get those shifts perfect, cruising down the road with the windows down and the sun out... that is the greatest feeling in the world.

 

The best moment ever is when you're up shifting an 18. You flip the selector to high range, then shift up to the next gear. Get on the throttle and that turbo spools up and sings. Gets me every time I'm lucky enough to take a truck out on the road.

 

Oh, don't I know it. C-15 twin turbo, 41 psi of boost, loaded 130,000 lbs and a monster dump on the wastegate. She sings in every single gear.

 

It's usually easier for people to start out double clutching and swap to floating after they master the double clutch.

It's much easier to hands on show somebody how to shift that it is telling them how on a forum. If you are trying to time your speed and rpm by the gauges, you're putting too much thought into it and you'll miss a gear before you get everything just right. You just have to remember what's going on in the transmission. You have two gears trying to go together and you have to get those gears to at least close to the same rpm. Upshifting you have to let engine rpm fall enough to match the higher trans gear. Downshifting you have to increase engine rpm to match the lower trans gear rpm.

 

The double clutch is something to enjoy for me. The worst part is missing a gear shift while running the mountains.
Frustrating, time consuming, and always worrying about engine temps in the hot summer.