shift without clutch?

[formula]

Anyone do this on a regular basis? If so, why?



FWIW, my trans shifts fine using the clutch. Just curious if anyone is doing it.



I know with some of the plow trucks I drive that it's pretty much a must to NOT use the clutch unless you're taking off from a stop.



Sean

 

[lmills]

I believe it is the gears are not cut the same in these light duty trannies like they are in the heavy duty truck trannies. You can shift without using the clutch but can expect increase synchronizer wear.

 

[DjFire07]

I don't use my clutch very often. It's just more convenient most of the time. Mine shifts very smoothly with or without it. I did "grind" a few until I got the feel for it.



DJ

 

[Mathew Clausen]

Synchronized vs non-synchronized

There is a big difference between heavy truck non-synchronized transmissions and a synchronized in our dodges.



With a non-synchro trans, there is nothing to get the mating gears to the same speed. So - you have to match the engine speed to the rpm needed for that gear. If you have the clutch pushed in, the engine does not turn the input shaft so you cannot control the speed of the gears. Hence - you need to have the clutch released in order to "manually synchronize" with the throttle. Many drivers use the "double clutch" method ... clutch in to get out of gear easily, then release clutch and match engine speed, then stab the clutch again to ease make sure there is no load on the gears as they are engaged. The nice thing about a non-synchro trans is that you can feel the gear cogs and more easily tell what engine speed you need.



For our transmissions - shifting without the clutch is tricky and you need to use caution. If you match the engine speed perfectly - there isn't any issue and the next gear should fall in. If you don't it is hard to tell because you are up against the synchro and cant feel any grinding. At this point if you just pull harder, you are now making the synchronizer try to match the engine speed to the vehicle speed. It is not designed to do that - and that is where damage (or accelerated wear) can occur. The synchronizers are designed to speed the input shaft and clutch disk up and down, not the whole engine. Double clutching is probably the best approach as this way you get the gears to almost the same speed, and then the synchros only have to do a little work.



Whew - too much writing but hopefully it makes sense!



Mathew

 

[scootergmc]

There is a big difference between heavy truck non-synchronized transmissions and a synchronized in our dodges.



With a non-synchro trans, there is nothing to get the mating gears to the same speed. So - you have to match the engine speed to the rpm needed for that gear. If you have the clutch pushed in, the engine does not turn the input shaft so you cannot control the speed of the gears. Hence - you need to have the clutch released in order to "manually synchronize" with the throttle. Many drivers use the "double clutch" method ... clutch in to get out of gear easily, then release clutch and match engine speed, then stab the clutch again to ease make sure there is no load on the gears as they are engaged. The nice thing about a non-synchro trans is that you can feel the gear cogs and more easily tell what engine speed you need.



For our transmissions - shifting without the clutch is tricky and you need to use caution. If you match the engine speed perfectly - there isn't any issue and the next gear should fall in. If you don't it is hard to tell because you are up against the synchro and cant feel any grinding. At this point if you just pull harder, you are now making the synchronizer try to match the engine speed to the vehicle speed. It is not designed to do that - and that is where damage (or accelerated wear) can occur. The synchronizers are designed to speed the input shaft and clutch disk up and down, not the whole engine. Double clutching is probably the best approach as this way you get the gears to almost the same speed, and then the synchros only have to do a little work.



Whew - too much writing but hopefully it makes sense!



Mathew

That's one of the best and most precise explanations I've ever seen. Good Job.

 

[dan shss]

I shift without the clutch about 90% of the time,,Only if im speed shifting our racing my friends duramax then I will use the clutch to shift faster. .



Im teaching the wife to shift without the clutch and she can almost to it,,even pulling the horses

 

[nickleinonen]

i've done it a few times, but the extra wear potential keeps me from doing it constently... clutches are much cheaper than synchros anyways... and i find upshifting much harder than downshifting with no clutch... the engine speed drops too quickly with no throttle once you float it out of gear going up the gears... i need to give it throttle to maintain [slow the drop] the rpm to get the gears to match speeds. . if i am going through that trouble, the clutch is quicker. downshifting though, goes smooth as butter as you need to blip the throttle to match speeds anyways. . easier to do on non synchro trans, and bigger engines with heavy flywheels... engine speed drops slower

 

[Badunit]

The explanation above is the best I've seen for NOT shifting without the clutch. The clutch isn't that inconvenient or difficult to use, I don't really see any point in avoiding its use other than maybe the "coolness" factor of being able to shift without it.

 

[formula]

I'm aware of the differences of synchro / non-synchro transmissions. Just interested to see if anyone was regularly shifting without the clutch, how it works out, and why they do it that way. FWIW, I'll continue using my clutch. It's quicker and easier that way, especially when doing an agressive double-clutch downshift



Sean

 

[LRundberget]

Only when I have to, like when the clutch goes out. The helical cut gears in most transmissions are not condusive to shifting without a clutch or syncros. The rigs that are normally shifted without a clutch have straight cut gears which allow the gears to mesh easier. But straight cut gears are also very noisy. You will find most straight cut gear transmissions in the heavy equipement and racing industries.

 

[srichard]

there is absolutely not a single reason to shift a synchorized gear box without the clutch. as it has been mentioned before, some racing boxes are straight cut (dog boxes) and un-synchronized to allow you to shift faster. you need to double clutch them on downshift though. They also tend to be more durable. On a truck such as ours, you're just trading minimal (if any) wear on your cheap clutch for medium to heavy wear on your expensive transmission. whatever.

 

[Cattletrkr]

Dad's FLD 120--no prob shifting it without clutching all day long



My 2 Dodge's--Can't seem to get the hang of it in 4+yrs and two diff trucks. Hate grinding noise. Easier to double clutch than to no-clutch.

 

[Mokerz]

I have never shifted with the clutch in any of my 18 wheelers. In my 93w350 I don't use the clutch becaus the syncros are already wore out 350,000 miles. However in my 97 2500 5spd I use it, because the sycros work fine and the transmission shifts great, it only has 100,000 miles. I do double clutch it a lot, and find myself trying to match RPM's. Unless I am trying to spank a corvette or something. :-laf

 

[Mokerz]

basically srichard has got it exactly right

 

[BTighe]

i didnt use the clutch for a while but after a few grinds its really not that cool anymore. also it takes too long for the engine speed to match up. maybe if the ratios were closer it wouldnt be so bad

 

[nickleinonen]

The helical cut gears in most transmissions are not condusive to shifting without a clutch or syncros. The rigs that are normally shifted without a clutch have straight cut gears which allow the gears to mesh easier

um, the gears are always in mesh on our transmissions, and on big rig transmissions [be it straight cut or heilical cut]... the shift collars connect the power from the gear to the shaft, and they have straight dog teeth on them in both big rig transmissions and on our transmission... you don't physically move any gears around in 90% of transmissions [except maybe for a reverse idler gear]

 

[hemijustin]

I rarely use my clutch. Unless racing ... I haven’t had any problems with the transmission. I don’t do it because its cool. its just that to me its just as easy or easier not to have to move my left leg every time I shift ( 6 speed with 4. 10 gears= alot of shifting. My brother in law has a 96 with a NV4500 he has had the truck since new he never uses his clutch. Only for take off and reverse. He has a little over 200,000. Miles the only problem he has had is he smoked his clutch puling a cement truck out of a pounding basin. And his fifth gear fell off at around 170000 something. The guys in the shop said it was one of the best looking trannys they ever taken apart. Actually they said it looked brand new besides fifth gear laying in the oil pan. So as for me im not going to stop my “bad” driving habits.

 

[E7mack96]

My take

I rarely use the clutch in any vehicle. Ever since my days in a 1988 Ford Ranger 5 speed (bought new in 1987), I have floated gears. I have not had any transmission failures yet. I learned to float gears long before I started driving big trucks. It actually helped that I could do this already. I was the only one at this company I just started for that could drive an 18 speed. And on the 1st day, no less.



I do it because I can. I do it because I want to. I do it because I don't care about th consequences. I do it becaues, if I mess it up, I can afford to fix it. (knock on wood for that one, lol)

 

[JeffWhite]

um, the gears are always in mesh on our transmissions, and on big rig transmissions [be it straight cut or heilical cut]... the shift collars connect the power from the gear to the shaft, and they have straight dog teeth on them in both big rig transmissions and on our transmission... you don't physically move any gears around in 90% of transmissions [except maybe for a reverse idler gear]

Amen. I have been thinking this

but wasn't gonna say anthing, cause my first hand exp. with trannys was

with Muncie 4 spds. That is the situation with them, also correct on the

reverse idler in them - have seen teeth chipped from jamming into rev.

Another part I havn't seen mentioned is the "blocker rings" snap ring that

is what you feel when it pops into or out of gear. A broke blocker ring

will let it jump out when the throttle is lifted, just from a bump in the road

or the weight of the shift lever... When we grind a forward gear, if what

we felt and heard was the actual gears grinding, about one or two grinds

and you wouldn't have teeth on them anymore!

 

[SHobbs]

Count me in on this one. I never use the clutch exept for launch. Never had any problems or failures. I have eevn figured out how to get into 1st if I am slow rolling without stopping. I had a 90 Ford with a 460 a few years ago and never used the clutch, after 249k miles the only problem was that the throw out bearing failed, the transmission never failed. Every truck I have owned has been a standard shift and all of them I floated.