Does anyone double-clutch?

[Yohan]

A neighbor told me that shifting the Deuce would be smoother if I double-clutched. I tried it (clutch in to take it out of gear, disengage clutch, clutch engaged again and place it in to higher gear) and it did seem to shift smoother.

Does anyone here double clutch and is there any reason one shouldn't do it?

*** I searched for this topic before posting to keep the Search Nazis happy. My apologies if I missed a similar thread that covers this topic!

 

[bassetdeuce]

Only on a downshift sometimes.

 

[Yohan]

Should one only double clutch on the down-shift or can it be done while up-shifting as well? I only tried it while up shifting, but I only went a couple miles (one stop sign and slowing down to turn into my drive way). TIA!

 

[Stan Leschert]

That is the textbook recommended way. I only use the clutch to start from a dead stop. Yes, I do hold a CDL and have been paid to do this for 20+ years. On a civvy vehicle (syncro) learn how to speed shift. Bring the engine up to revs, back off slightly on the throttle, and put light preassure on the shifter. When it is ready, it will disengage. Move the shifter to the next desired gear, and when the revs have dropped to just over high idle speed, it will go in. DO NOT FORCE IT. This will take a bit of practice but you will learn it. Try it on your toyota Tercel, before you try to grind your Deuce. I am sure that many more people will give you much more precise instructions, but here is a starting point.

The best advice that I can give is to find a buddy who will take you out for a tour and show you how to do this.

 

[armytruck63]

I double clutch, especially when the transmission has not yet come up to full operating temperature. I find it makes shifting easier, though it is not necessary. Double clutching seems to be a bigger help when downshifting - give the throttle a little bump when you pass through neutral.

I have driven my buddy's 1941 GMC CCKW and double clutching IS needed on that truck because it has a non-syncromesh transmission.

My son-in law, the big rig driver, only uses the clutch when starting out in first gear. All other shifts are done when letting up on the throttle slightly. We're talking a 13 speed fully syncromeshed close ratio transmission that was made for no clutch shifting. I haven't got the skill or nerve to do this in my deuce.

My advice would be to double clutch and see if you like it better. You certainly won't hurt anything by trying.

 

[Yohan]

My step father was a trucker for most of his life and taught me how to speed shift! I used to do it in my little Chevey Chevet and later my Chevy Spectrum. I first recall him telling about an argument he had with another guy who said it was impossible to shift a truck without using the clutch. It was then that I asked him to explain it to me. I tried it in my junker car and it worked. You had to have the engine at the proper RPM, but I found it to be quite easy. Thanks for the replies!

 

[kurtkds]

I double clutch also.. Defiantly shift nicer when the tranny is cold.

I have tried to speed shift in the deuce, I can do ok at it, but I don't feel real comfortable doing it.

 

[bassetdeuce]

Synchromeshed? I don't think there are syncros in the Eaton-Fuller or Meritors. Big rigs use straight cut gears for all of the gears, and use evenly spaced ratios across the board. This gives them the predictable "feel" needed for clutchless shifts, as mentioned in the above post. For the deuce, double clutching reduces syncro wear and is less shocking to the driveline. Tradeoff is more wear on the clutch linkage and throwout bearing if not kept greased.

 

[datsunaholic]

Double-clutching and speed shifting was the only way we could shift one of the 5-tons we had in my reserve unit. Double clutching only worked so much, the syncros were completely bad on that truck. Got really good at speed-shifting it, but one day we had just switched out drivers (I'd just logged 150 miles) and was on the passenger seat when we managed to have the brakes fail, on a hill of hairpin turns, downhill, towing a 33 ft patrol boat. Downshifting was near impossible but we made it down safely (if not soundly). The driver was a truck driver by trade, so that helped. He forced that thing into a lower gear so hard it managed to engage the surge brakes on the boat trailer... lifesaver.

 

[Ferroequinologist]

I double clutched the 818 when I was hauling ties, as a long time CDL driver rode with me several times and taught me how. I've since started doing it in the deuce. I don't blip the throttle in between, or let the clutch back out. I push the shifter lightly, and then push the clutch down until the shifter pops out, then go the next gear, and bring engine RPM close to that gear for that speed, and let the clutch back out. I can do it in split seconds now, but it was rough while learning. It shifts WAY.... smoother, especially the 5ton.

 

[DieselBob]

When I first started driving “Big” trucks we had 5-4 twin sticks (B63 Mack) and a more seasoned driver gave me a nice tip. When you start the truck in cold weather leave the aux shifter in neutral and the main box in second while you do you pretrip. This will let the 90W tranny oil warm a little bit, it won't be up to operating temp but won't be tar either. When I drive the deuce I do the same thing. Tranny in 2nd and transfer in neutral while I do the walkaround and check the brake fluid etc.

This is the style trans I learned on. Wish the deuce had this. So much easier with no syncros and a gear for every need.

Shifting a Mack B Model

 

[bigmike]

I double clutch always. I find it shifts smoother.

 

[greenjeepster]

Nope... I never double clutch or slide shift any truck that it is not required in.

Double clutching a sycromeshed transmission does nothing to improve shifting unless you already have problems with the tranny. It does save on wear of the syncromesh gears, but so does not driving the truck at all

Slide shifting should not be done if you are not good at it... It can damage the transmission if you don't get the rpms just right. It is better to practice that move on somebody else's truck before using it on your own.

Diesel Bob is nuts I wouldn't mind if I never see another compound transmission in a truck in my life... I would not own a deuce if it had one

 

[nk14zp]

I clutch on starts and stops.Not while shifting.

 

[FireFighterHill]

On my father in laws Deuce, if you dont double clutch, it grinds every gear except 5th.

 

[DieselBob]

Diesel Bob is nuts I wouldn't mind if I never see another compound transmission in a truck in my life... I would not own a deuce if it had one

I will concede that was the main reason that I never owned a personal vehicle with a manual, until the deuce. After spending all day doing that the last thing I wanted to see when I got in my pickup was a shifter.

 

[nkawtg]

Cool link DieselBob.....always wondered how they were operated. Thanks for posting!

 

[kbush]

I double clutch changing up and down.

 

[jmh4x4]

i double clutch all the time, seems to be a lot smoother

 

[bassetdeuce]

No vehicle I've ever had shifted as bad as my old SAAB 900, with a bad cable clutch, worn pressure plate and cracked trans mount. I understand what Dieselbob is sayin, for me the sticks belong in the BIG trucks and Jeeps. Autos for everything else.