"floating the gears?"

[grincon]

I've heard of floating the gears(after take-off, shifting without the use of the clutch at certain rpms) in the big rigs. Is it possible to do the same with these Cummins? If so, how, and what are the rpms?

 

[M Barnett]

No, it isn't the thing to do with our trucks because they are synchronized transmissions. Big truck trannys are not synchronized so you can easily feel the gears by lightly putting pressure on the shift lever. With our trannys, you have no feel. I sure wish my 5 speed wasn't synchronized.

Michael

 

[CumminFast]

I can shift w/o the clutch in my '99 5-speed. I usually shift around 1800-2000 rpm. Hope it doesn't hurt anything.

 

[FL70CAT]

Can you remove the syncros when the transmission is out??

 

[DT]

Heck, I even shift without the using the clutch in my '93 jeep wrangler with a 5 speed... :-laf :-laf

 

[speedracer]

bad idea

I've been told by people I have reason to believe, that shifting a synchronized transmission without the clutch is hard on the synchros. It's also easier on a big truck transmission because the ratios are closer than on our trannys.

 

[juicedcummins]

If you have the touch go for it! If you don't and grind or clunk, use the clutch.

As far as the 5 speeds they are real easy to shift clutchless with an inline 6 like our 5. 9's.

The 6 speed is a little tougher to master.

 

[Motorhead]

Big rig gearboxes are usually straight cut gears that are designed that way for strength. A synchro box uses diagonal cut gears because they are quieter. The synchro is a brake of such to speed or slow the mating gear to the same speed before it engages the teeth of the gears. You are not doing your synchro trans any favors by not using the clutch. If you were somewhere in the middle of nowhere and you needed to get home because your clutch wouldn't dis-engage, I would go for it, but only in that case.

My . 02 Chris

 

[Mundgyver]

It's a good thing to know incase you wind up loosing a clutch. I used to practice this type of shifting about 35 years ago with my Dad's Ford. If you have the knowledge and skill to do this, it will get you out of a bind if you loose the ability to disengage the clutch and you are in the middle of nowwhere. With the newer transmission and syncros, I'm not sure how well they would last if this was done on a regular basis though. Enjoy the practice.

 

[NVR FNSH]

Originally posted by juicedcummins

If you have the touch go for it! If you don't and grind or clunk, use the clutch.

As far as the 5 speeds they are real easy to shift clutchless with an inline 6 like our 5. 9's.

The 6 speed is a little tougher to master.

What am I missing here? How does the inline 6 make it easier to clutchless shift?



Brian

 

[SOOT]

When I shatter the center hub in my Moms truck back in March I was on the interstate headed home to get through town I had to shut the truck off at every red light put it in gear and then start it in gear then float the gears so I could get it home.



Since I work as a big rig mechanic when I drive one I always float the gears with them, and comparing shifting them to our syncronized trans it is a lot easier to float the big ones.

 

[WadePatton]

watch the tach

and if you make lots of grindy noises--use clutch.



Using the clutch follow the RPM drops for each upshift. Then you'll know where the ENG/TRAN want to be for the shift. The gaps will be the same downshifting-but up in R's not down. (Learn the splits) and remember that you'll be losing road speed while trying to match that RPM-so it'll get lower if you don't make the match quickly.



I've driven BMW, Porcche, VW, 3 FORDS CLUTCHLESS SHIFTING and even rolling shifted a farm tractor the other day (NOT recommended).



I haven't tried the NV5600 yet, but that's because I'm just now getting to know the gearbox.



I have no fear of "floating gears". If you can do it without grinding metal or jerking the driveline, it can't hurt a thing.



Shift for brains

 

[WadePatton]

and the sound

I pat the foot-feed once or twice on every shift up or down--so it sounds like i'm floating gears. I'm just practIZing-. and it sounds so good.



Speaking of sound--walked by a running PS last night--what a wheezie sound!



and YES MOM drives a CUMMINS! see earlier sig. :--)

 

[E7mack96]

floating

I float on all upshifts and downshifts. Have always done it. all the way back to an '84 toyota 4x4. I will agree, however, that if you grind it, then you should be using the clutch.

 

[Gary - K7GLD]

ALSO be aware that ONE miscalculation, and you may well chip a gear - or WORSE... Shifting a synco gearbox WITHOUT use of the clutch can be much like Russian Roulette... Seems sorta pointless, when there's a perfectly good set of syncros down inside that transmission intended to protect the gears...

 

[illflem]

Originally posted by Gary - KJ6Q

Seems sorta pointless...

I agree, you guys have weak left feet or something

 

[TBrown]

I drive different trucks part-time, dump truck, and semi. Most of them I don't ever use the clutch. Except for an old 4 speed by four range spicer in an old international, that had to be clutched. But with the Fuller trannies in most trucks I can shift better and faster with the throttle. But in my truck using the clutch is the only way to go, it is faster by far and much easier on it also. The synchros are going to have a hard time lasting the way it is with out excess abuse.

Tony

 

[WadePatton]

well

I don't do it all the time. I just do it because I CAN.



And I learned how one night _long story_ but I lost the clutch on a 3-on-the-tree as a teenager and learned it by necessity.



It's like teaching someone to drive a stick (using the clutch). They may never choose to--but if the HAVE to they can. Oo.