Double clutching Help!!!!!

In our CDL class we spent the first few days upshifting only, in a parking lot. So we never got out of the low range on a 10 speed. So we never got over 15 mph and did not have space to even try to down shift. Some guys would only hit 3rd gear double clutching. If we hit 4th gear we were shifting as fast and efficent as possible, and then you were on the brakes good so you didn't hit hte curb. And we were starting out in 2nd gear!!!
This was a temporary setup for the school, but it taught us about tight spaces. We also did our backing skills and parking skills in this parking lot. It would take about a minute to back across the parking lot, at idle speed with a trailer. If you revved the truck up to 1200 rpm you could get across the lot in 30 seconds.

The school taught us to double clutch, so we would pass the DOT testing, which requires you to double clutch.

It takes a full second (a heartbeat like someone else said) for the engine rpms to drop down so you can upshift.....whether you double clutch, single clutch, or no clutch....until that engine speed drops you are not getting it into the next higher gear.....period.

On my first job I switched to single clutching and after about 10,000 miles I started to shift without using the clutch, which is what my boss wanted his drivers to do. This was in an 18 speed Peterbilt, and he wanted you to run through all the gears and not skip any. He also wanted his drivers to keep their right hand on the shifter all the time when going through the gears so you would not forget what gear you were in.....this was driving milk tankers that were smooth bore, so you had to take it easy on the throttle, otherwise you would have a one hell of a surge going on. Using the gear splitter actually caused more of a surge than using the clutched gears because you had to let off the throttle hard to get the tranny to shift on a split gear. Sometimes I would use the clutch lightly on the split gears so I wouldn't have to let off the throttle hard to get the next gear and have less surge.

We usually ran with the tank half to 2/3rds full, so the surge is worse then than if the tank is full. I only pulled one full tank and there was no surge that I could detect....it was FULL of cream and they ran it over filling it.

 

The best piece of advise I can give you is listen to the engine as it revs up. Learn what the shift points sound like. After you have done it a few times you will find it to be easier than watching the tach. Also don't force a gear change. I was a trainer many years ago. I used to have the students start out running the rpms all the way up and tell them "clutch in-neutral-clutch out-clutch in -move the shifter" After numerous successful gear changes I would move on to teaching them progressive shifting. I found that if I remained calm and offered encouragement to the student they were able to learn a lot quicker. As far as down shifting watch your ground speed as well as the tach. If the max rpms is 2150 and your idle speed is 650 rpms then you want to downshift at 1500 rpms (2150-1500 = 650). At 1500 rpms rev it hard (you won't hurt the engine) once you are in neutral and move the gear shift. If your rpms fall below 1500 then you don't want to rev the motor as hard ( I call it a baby rev).

 

dont forget to make sure you have the jake on at the TS too so we all hear you race around
the other day i G O A L twice just to be an ##### because of speed racer
and still didn't hit anything

 

I don't understand any of this at all, and probably won't until I get behind the wheel. The biggest thing I don't get (from the CDL guide/test) is why you "speed up" (RPMs?) to downshift, and "slow down" to upshift...

 

Relax

It just takes practice

One day it will all come together, then you will think it is not that hard. Does your school have a yard to practice in without traffic?

 

Well folks downshifting gets the best of us - such a humbling/humiliating "STILL ONGOING" experience...

Especially when your 50 and having driven manual, and motorcycle with little glitches throughout the years, and a shorty BS' ing 19 year old who cant get the seat adjusted for his feet to hit the pedals and drives consecutive days like he has driven trucks for years, really F#$kS WITH u....At least I have competition that is also grinding em ...

My analogy - everyone knows the old saying - cant walk and chew gum at the same time...

This downshifting of coordinating multiple body/brain functions while focusing on the road and rig are STILL a bit system overload...

Can get it for now on the 9 but back to the pain in the ### 10 speed next week...

OH YEAH! hint for fellow students not mentioned often is - dont push in the clutch until you use the brake ALONE while slowing the truck first (unless your completely stopping)... then after reaching next lower gear shift speed then do the clutch shift rev clutch shift .... If you push the clutch in TO EARLY while braking the trans shafts will be spinning alot further out of synch and become harder to mesh....

Oh, for my training it was first time behind wheel a couple spins around range and out to the public roads ...

Man !!! it is a stay focused and sweat it out experience !!!! HA!

dont step on the GAS when UPSHIFTING !!!! DOnt forget to take it WIDER! WIDER !WIDER! BLAH !! BLAH BLAH !!!

DONt forget what gear your in !!! As the arm/hand comes across and slams it into gear !!! Oh okay that will work!!!HA!!! Selector lever, Selector!!!!


GGEEZZZ!!!! HA !!! King of the GRIND!!! hee hee!!! bring it on!!!

 

Good point !!! The clutch brake can engage - and is only applicable for first and reverse...

I figured that out the hard way...

Guess it always existed in autos and bikes but never recognized it in those applications... it seemed to SYNCH better unlike the flintstone non-synchronized trannys... oops sorry

JUST ADD TO THE LIST ... HA !!!!

And yes Terrapin flyer I must pay mind to the gear speed association you reference as well as satisfying the 500 rpm window of shifting opportunity...

 

Yep, That's it, it is a job you know? On the other hand, you might land a job with a company running automatics and this would change everything.

 

Do you have any experience driving a stick in any other sort of vehicle? If you do, you know that when you downshift your engine revs up as you do it. It's because 40mph in 3rd gear is a lot higher RPM than 40 in 4th or 5th gear. To get the stick in gear you'll tap on the accelerator to increase your RPMs enough that the engine is close to what you'd be doing in that gear.



When taking the test, will the DOT require you to double clutch the entire time? I drive a yard horse at work and I'm told not to touch the clutch at all. I still find it easier to sort of single clutch, especially when downshifting, and in the lower gears, where it doesn't want to let go of the gear it's in (I know, just tap the accelerator a little and it drops out of gear easy enough, but I'm not graceful about it). Unfortunately they just sort of said, "here, move this trailer" and I was never given any real training. An old trucker drove with me for the first trailer I pulled out and dropped, but aside from that I've mostly taught myself. I've spent an hour here and there driving back and forth across the parking lot and around the plant after the line went down early and everyone went home practicing my shifting. Will school give me that sort of time? I guess I should start practicing double clutching, huh?

 

I have, but it was years ago and I don't recall that I ever noticed that, but it's all good.