| Author | Message | ||
| hiwaycallin (Hiwaycallin)
Registered Member Username: Hiwaycallin Post Number: 21 Registered: 10-2007 Posted From: 208.98.218.205  Rating: |
Let me start out by saying (admitting, really) that I've never actually driven a real bus before, although I hope to remedy that condition before long. In the mean time I've been reading these boards everyday for months, and learning a lot in preparation for the day when I can finally scratch that itch (it's getting unbearable). A recent thread (Shudder in 1st gear in a 4106) got me thinking about shifting and also pointed me in the direction of R.J. Long's excellent article on the topic right here on this site. I was surprised to learn that R.J. advocates double clutching as a matter of course. I say surprised because I was under the impression that double clutching had long went the way of the dodo bird except in exceptional cases (shows how much I know). Now I've driven plenty of standard transmission vehicles in the past including medium sized trucks (5 ton), but have never employed the double clutching approach except for the odd time for fun when I was pretending to be a real trucker or race car driver. But after reading R.J.'s article, and spending a few hours on the internet reading many other similar such testimonials I now realize the virtues of double clutching for just about any type of standard transmission vehicle. So my question is not SHOULD double clutching be the norm, but rather, IS it the norm among Busnuts. Soooooo, do you or don't you??? | ||
| Douglas Wotring (Tekebird)
Registered Member Username: Tekebird Post Number: 321 Registered: 10-2004 Posted From: 71.59.75.212 Rating: N/A |
I advocate double clutching in any transmission which is non synched. Cars med duty trucks and even newer big trucks have synched tranny's. or even computer shifted manuals..... although it is possible to learn to shift without double clutching or clutching at all for that matter they were not designed for that kind of use and you may do significant damage/wear learning | ||
| marvin pack (Gomer)
Registered Member Username: Gomer Post Number: 219 Registered: 3-2007 Posted From: 76.4.151.87 Rating: N/A |
I will agree with tekebird.. On a manuel tranny that even has synced tranny I still double clutch the rascal because to me it is easier to shift and becomes natural after a while. On some that has a stiff clutch assembly I always use the clutch to start and stop not shifting. YOu will find it is a challenge and after learning how, it will be fun for others to watch you do it without a clutch and they can't figure how you do it and don't tell them either LOL | ||
| David Evans (Dmd)
Registered Member Username: Dmd Post Number: 232 Registered: 10-2004 Posted From: 72.89.73.18  Rating: N/A |
we have two oldies, 3703 had a clark 4 speed that you could double clutch but usually could shift without the clutch mostly dc on the downshifts. The Silversides does not like to be dc for some reason. When we bought it i reveved her up and did the dc (was pretty proud of myself) and promptly screwed up the shifts! The owner said he never dc when shifting and so it goes. But now i just dont use the cltch. | ||
| Jim Wilke (Jim Bob) (Pd41044039)
Registered Member Username: Pd41044039 Post Number: 274 Registered: 2-2001 Posted From: 69.77.156.137 Rating: N/A |
I'm not sure about the other makes, but the GM manual trans buses upshift pretty well without the clutch once you get a feel for it. If the governor is right, when you reach top RPMs, say 2150, the governor pulls the rack back & you can feel the power instantly fall off, like you ran out of gas. When the power train unloads, you shift. That said, I usually just stab the clutch in & out while shifting, no broken teeth that way. Down shifting works just like RJ describes. As the bus is slowing (hill climbing) & the road speed gets to 5 mph higher than the top speed in the lower gear, clutch in & put in neutral. Floor the throttle (only goes to top governed RPM) and when the speedometer reaches the upshift speed in the lower gear, clutch in & the trans will drop right in the lower gear. As you learn your particular bus, you can learn to up & downshift at speeds other than the 20/30/50 type shift points. When you get about 7-8,000 miles driving around city & suburban streets, you will be able to shift at most any road speed by lightly revving the engine (in neutral, clutch out) & with a VERY light pressure on the shift lever, feel the gear speeds matching until they match. Don't pull so hard it grinds, you should just feel a "purr" of teeth on teeth slowing or speeding 'till they match. Someone in the middle of the bus should not hear this "purr". Know that you can ONLY shift into a gear that is appropriate for the road speed. I rode on a 'Hound Scenicruiser about 600 miles when I was a teen, and sitting right up front, I did not realize the bus was a stick, the driver did this so well. There was just a sound between "click" & "clunk" as he moved the stick, no lurching or grinding. I have several "big truck" driver friends. They try to shift my 4104 fast like a truck & all say it can not be shifted fast. The governor responds gently & more slowly, and the trans is a wide ratio unlike the normal big truck with 9 or more speeds. | ||
| Tim Brandt (Timb)
Registered Member Username: Timb Post Number: 147 Registered: 10-2003 Posted From: 74.244.14.221  Rating: N/A |
I am very new to this as well but at least with my coach, a Flxliner with a 6-71 and a Spicer 5 speed, it doesn't seem to need double clutching on the upshift at all as long as you upshift between 1500 and 1700. Downshifting does require doubleclutchig. I don't think I could be doing any damage as it slips right in on the upshift no funny noises or anything. If I'm wrong please correct me | ||
| marvin pack (Gomer)
Registered Member Username: Gomer Post Number: 220 Registered: 3-2007 Posted From: 76.4.151.87 Rating: N/A |
hey Tim. Do you feel and hear gears grinding? If you do you are not doing it right, if you slip the sucker in and out without feeling or hearing gears grinding, then your are doing just fine. Keep up the good work. Gomer | ||
| Don Evans (Doninwa)
Registered Member Username: Doninwa Post Number: 109 Registered: 1-2007 Posted From: 66.45.175.118  Rating: N/A |
No substitute for practice. Either way, with or without clutch done properly works just fine. Either way done poorly can shock load the drive train. It is usually easier in the typical OTR truck because you have MUCH less linkage to deal with. I have a little single screw day cab with a 350BC Cummings on a 9 speed but only use it a couple times a year. Only has 285K on it and is very tight. Both with it and the new bus (old bus was syncro) get mostly double clutched because I just don't drive them often enough to get used to them. After a little driving though, I find myself still pushing the clutch out of habit but not necessarily enough to release it. For me double clutching became a habit working harvest where you were jumping from truck to truck, with different drive trains. Helps too when you need to 'rush' the shifts on soft ground or pulling steep hills at real low speeds. Don 4107 | ||
| Tim Brandt (Timb)
Registered Member Username: Timb Post Number: 148 Registered: 10-2003 Posted From: 74.244.14.221 Rating: N/A |
no grind at all. I do know the feeling you mean though especially if you try to pull her into first before it's completely stopped | ||
| Laryn Christley (Barn_owl)
Registered Member Username: Barn_owl Post Number: 248 Registered: 10-2006 Posted From: 72.66.181.54  Rating: N/A |
Right out of High School I got a job driving a dump truck. It had a 13 speed and I shifted my a$$ off (don’t worry, it grew back). By the end of the day my leg and back would be killing me, even at that young age. I complained to some “Old timers” and they told me to quit using the clutch. I had no idea that this could be done! Needless to say I ground the stink out of that tranny as I learned to master clutch-less shifting. But boy, when I got the technique down, I could shift better without the clutch than with it. Smooth as silk. I have found that it is somewhat like bike riding for me. Once you get the “feel” for it you don’t have to relearn it. I have for fun, shifted all types of manual transmissions without the clutch, and no grinding. Exercise a little self discipline, don’t ever force it, be patient, use light pressure, and the shifter will just fall into place. I would be reluctant to do it too much with a transmission that had syncros because the light pressure used might cause premature wear on them. If I had a manual in my bus I would go without the clutch, even though there is a possible risk from it. I am very comfortable with it, and I enjoy doing it, because after all of those years of pratice I have gotten good at it. | ||
| FAST FRED (Fast_fred)
Registered Member Username: Fast_fred Post Number: 273 Registered: 10-2006 Posted From: 66.90.226.247 Rating: N/A |
The governor responds gently & more slowly, and the trans is a wide ratio unlike the normal big truck with 9 or more speeds. And if the throttle cable is NOT serviced , so the RPM drop is as rapid as designed , shifting is even more of a wait chore. FF | ||
| Jack Hart (Jackhartjr)
Registered Member Username: Jackhartjr Post Number: 16 Registered: 8-2007 Posted From: 64.12.117.73 Rating: |
Have not all of the post's, however let me relate this to you; An old mechanic showed me the gears out of two transmissions. One had broken teeth and looked rough! The other had little wear. He said, "The ones with the broken teeth and all of the wear came from a truck in which the 'PROFESSIONAL' driver never double-clutched! The good gears came from a truck where the driver always double-clutched!" Nuff said! Jack | ||
| Paul Lawry (Dreamscape)
Registered Member Username: Dreamscape Post Number: 242 Registered: 5-2007 Posted From: 66.191.131.98  Rating: N/A |
I always thought double clutcing was just good insurance, so I always have in our Eagle with a four speed spicer. Haven't reached the good feel of doing it when down shifting though, :-(. Paul | ||
| FloridaCliff (Floridacracker)
Registered Member Username: Floridacracker Post Number: 374 Registered: 7-2004 Posted From: 24.27.228.156 Rating: N/A |
I never double clutch on an upshift, just run it to the govenor and it slips right in(most of the time  ) On the downshift I double clutch, Mainly because I havn't needed to downshift all that often and it seems to work best. Cliff | ||
| Kyle Brandt (Kyle4501)
Registered Member Username: Kyle4501 Post Number: 404 Registered: 9-2004 Posted From: 65.4.175.28 Rating: N/A |
Jack, I heard lots & lots of noise from my transmission when I tried double clutching. . . Much Much quieter when I just stabed the clutch & pulled her out of gear & let her 'drop' into the next gear. That old timmers 'show & tell' means little without more facts. . . . Now If it was known that both made quiet shifts . . . that'd be different. The ONLY way you can wear down the teeth is by trying to force it into a gear before the speeds match up. Different driving styles & linkage play make a difference. All that said, I'd still pay attention to how the former driver shifted it & use that as a starting point. If he sucked at shifting, you will know what not to do! | ||
| FAST FRED (Fast_fred)
Registered Member Username: Fast_fred Post Number: 274 Registered: 10-2006 Posted From: 66.90.226.229 Rating: |
Haven't reached the good feel of doing it when down shifting though, :-(. The 5c fix is to place a marker (dot of paint) on the max rpm in each gear. AS you near the marker slowing down , select neutral FLOOR the throttle for Max rpm , and it will slip in with nary a sound. MR Long explains it all in his shifting article. FF | ||
| Paul Lawry (Dreamscape)
Registered Member Username: Dreamscape Post Number: 243 Registered: 5-2007 Posted From: 66.191.131.98 Rating: N/A |
FF, Good point. I have read and re-read his article. I think I just need more time on the road, adjust the linkage and give it a workout. Other than that it's no big deal. Also need to shift slower, not like driving a sports car for sure. I'll get the hang of it. I don't mind shifting at all. | ||
| Buswarrior (Buswarrior)
Registered Member Username: Buswarrior Post Number: 1233 Registered: 12-2000 Posted From: 76.68.120.242  Rating: N/A |
Hello. We need to know our sources.... For a busnut, I am an advocate of using the clutch as intended until you are EXCELLENT at shifting it up and down seamlessly and without a thought or worry. And I'd encourage you to keep on using it. After you are excellent, if you feel like it, please, do experiment and have some fun, since you are less likely to harm things. If you are a hardcore clutchless shifter, I'd still encourage using the clutch on downshifts in your bus, single pump, to slip it into the next lower gear, because of the forces involved in having the engine at high RPM. This topic keeps coming up, and requires a lot of typing. Stay tuned.... happy coaching! buswarrior | ||
| Jack Hart (Jackhartjr)
Registered Member Username: Jackhartjr Post Number: 17 Registered: 8-2007 Posted From: 64.12.117.73 Rating: N/A |
After reading these posts...I get the feeling that a lot of folks are still apprehensive about downshifting. I always thought that downshifting was a lot of fun! Shoot...get out on a lonley road and practice till you can go all the way down through the gears! JAck | ||
| Gus Causbie (Gusc)
Registered Member Username: Gusc Post Number: 629 Registered: 11-2005 Posted From: 70.171.233.117  Rating: N/A |
Clutchless shifting the Spicer 4sp on my 4104 is just as easy as DC. I grind the same amount of times either way because matching engine and tran speed is the deciding factor. Using the clutch is a waste of time and effort not to mention wear on the clutch. If your clutch is not properly adjusted it is even better to shift without it. I used to drive an 18 wheeler and have a few antique big trucks, I never use the clutch on any of them while under way. Each tran is different. It takes practice. DC helps the macho big rig driver feeling but otherwise it is not of much use. | ||
| Austin Scott Davis (Zimtok)
Registered Member Username: Zimtok Post Number: 242 Registered: 9-2006 Posted From: 216.37.73.226 Rating: N/A |
I ALWAYS double clutch UP through the gears. (it's faster then just waiting for the gears to match in speed) When downshifting I let the bus come down in speed to where shifting down to the next gear is possible. I then slip it out of gear and bring the engine RPM up to match the lower gear speed and it slips right into gear. | ||
| R.C.Bishop (Chuckllb)
Registered Member Username: Chuckllb Post Number: 256 Registered: 7-2006 Posted From: 4.240.214.109 Rating: N/A |
Zim...how does one do that going "downhill"???...without using brakes.  RCB | ||
| Larry Baird (Airhog)
Registered Member Username: Airhog Post Number: 138 Registered: 1-2001 Posted From: 159.115.176.12  Rating: N/A |
I DBL clutch my 8V71T with a 10 speed RTO, I put it in and out when I leave and then again when I stop. No waiting for the RPM with a 300 split and no grinding but don't get lost. | ||
| Gus Causbie (Gusc)
Registered Member Username: Gusc Post Number: 632 Registered: 11-2005 Posted From: 68.105.143.250 Rating: N/A |
A 10sp is designed for clutchless shifting. | ||
| Austin Scott Davis (Zimtok)
Registered Member Username: Zimtok Post Number: 243 Registered: 9-2006 Posted From: 216.37.73.226 Rating: N/A |
R.C. When going downhill the engine will slow the bus some depending on the grade of the hill. I do have to use the brakes in some of the downhill situations, and sometimes there is not enough time to slow down using the gears so I just use the brakes. | ||
| R.C.Bishop (Chuckllb)
Registered Member Username: Chuckllb Post Number: 258 Registered: 7-2006 Posted From: 4.240.213.226 Rating: N/A |
Zim...RJ Long and many others espouse going down hill in the same gear that one uses to climb the hill, I agree.... ie, in a 10 speed, going down a pretty good incline, one could not expect to have the coach slow down, rather it would tend ( sometimes BIG TIME) to accelerate. In the west we have big, long, and often steep hills. In the east, many short and steep hills. My experience is that it sometimes very difficult to downshift under certain uncomfortable circumstances....and I have Jakes. We have just learned to anticipate and drop into a lower gear at the top, keeping speed and rpms under control for additional downshifting, if necessary. Seldom use brakes going downhill; usually only if someone in front of me causes a situation to make it feasable. Just my way. RCB | ||
| Gus Causbie (Gusc)
Registered Member Username: Gusc Post Number: 635 Registered: 11-2005 Posted From: 68.105.143.250 Rating: N/A |
I've never shifted my 4sp down anywhere in the west even though we've been on most of the Interstate grades there plus a bunch off the Interstates. Third gear on a 4104 is awfully low unless you like to hear a 671 scream. I always top a grade at slow speed and brake as needed - no Jake - and fourth does a very good job of controlling the speed. It is much more effective than I expected a two stroke to be. I've never had a brake overheating problem. | ||
| Austin Scott Davis (Zimtok)
Registered Member Username: Zimtok Post Number: 244 Registered: 9-2006 Posted From: 216.37.73.226 Rating: N/A |
My mistake... I didn't clarify what I was explaining. When decelerating to a stop under "normal" conditions. (not steep hills) Such as: Off ramps from highways that can either be an uphill ramp or a downhill ramp. OR Surface streets that can have either a flat, uphill, or a downhill approach to intersections or turn-offs. I downshift as I explained above. | ||
| RJ Long (Rjlong)
Registered Member Username: Rjlong Post Number: 1372 Registered: 12-2000 Posted From: 67.181.166.160  Rating: N/A |
Hiwaycallin - Thank you for your kind words, they are appreciated. To answer your question, for me, personally, I still double clutch most of the time, but I'm getting lazy as I approach six decades. And with over a million miles under my belt in the industry (25+ years), I know how to double clutch, single clutch, skip shift, clutchless shift, etc. So I do whatever I want, depending on conditions and my mood. But automatics are becoming more and more appealing. . . LOL!! FWIW & HTH. . . | ||
| hiwaycallin (Hiwaycallin)
Registered Member Username: Hiwaycallin Post Number: 23 Registered: 10-2007 Posted From: 208.98.218.205 Rating: N/A |
Thank you all for your posts. This thread has been a real eye opener for me. There has been a lot of very helpful information put forth. I really appreciate it. | ||
| Ron Hansche (Texarkanaron)
Registered Member Username: Texarkanaron Post Number: 2 Registered: 3-2008 Posted From: 147.58.127.158 Rating: N/A |
Back when I was driving charters, the owner explained to me the length of the "cables" from the front shift leaver, to the transmission. He said that every time you miss a shift, or grind gears, it stretches just a little bit. Soon, there isn't enough "throw" in the shifter to make the gears in the back shift into the desired gears. He explained to me that as long as he was paying the driver to drive his bus, it would be driven the way he wanted it to be driven! Always double clutch, never "lug" the engine. Detroits like to be run up against the governor! |
