| Author | Message | ||
| Bob Symonds (Bob_symonds)
Registered Member Username: Bob_symonds Post Number: 22 Registered: 5-2006 Posted From: 146.235.66.52 Rating: N/A |
I can't get the hang of it. I have no problems upshifting with or without the clutch but downshifts are out of the question. When the tranny is hot it usually takes a good 15 seconds for the rotating shafts in the tranny to slow down just to get it into 1st from nuetral. Would thicker oil or gear lube help my situation? | ||
| Craig (Ceieio)
Registered Member Username: Ceieio Post Number: 287 Registered: 12-2004 Posted From: 206.212.230.165 Rating: N/A |
Bob - have you tried this? http://www.busnut.com/bbs/messages/12262/16204.html?1167073154 I have an auto bus, but have driven a few buses where you get to grind your own and this works just great, with practice. Craig - MC7 Oregon | ||
| John MC9 (John_mc9)
Registered Member Username: John_mc9 Post Number: 322 Registered: 7-2006 Posted From: 66.217.108.40 Rating: N/A |
"......it usually takes a good 15 seconds.......just to get it into 1st from nuetral....." It sounds like the clutch is out of adjustment. "I can't get the hang of it. "[downshifting] Try making a habit of up-shifting at the governed range, taking great notice at the top speed in each gear... It's easier then, to downshift by watching the speedometer, and bringing the engine to the governor prior to trying to shove it into the lower gear! It's tough to hear the engine speed to use as a shifting guide, so it's easier to just run up to governor...... After some time at it, you can use the amount of vibration in the shift shaft, as an indication of engine speed. I'd get that clutch adjusted correctly first, though... | ||
| Richard Bowyer (Drivingmisslazy)
Registered Member Username: Drivingmisslazy Post Number: 1901 Registered: 1-2001 Posted From: 75.108.82.12 Rating: N/A |
I do not think you should ever try to go from neutral to first if you have been sitting there with the clutch out. Try shifting into fourth first from neutral. Should be much quicker. Then without releasing the clutch, shift from fourth to first. Should not be any gear raking at all. Richard | ||
| Gus Causbie (Gusc)
Registered Member Username: Gusc Post Number: 350 Registered: 11-2005 Posted From: 71.112.176.74 Rating: N/A |
Bob, I assume you mean while in motion. If so, while in neutral, wait until you are almost stopped and it will slip easily into first. Just put a little pressure on the lever towards first and you can feel the gears equalize. On my 4104 if I stop while in neutral I have to shut off the engine before it will go into first. Going into higher gears before going into first has never worked for me. | ||
| Bob Symonds (Bob_symonds)
Registered Member Username: Bob_symonds Post Number: 23 Registered: 5-2006 Posted From: 146.235.66.52 Rating: N/A |
Well, my clutch is properly adjusted, if I go from nuetral to fourth and then to 1st it will grind going into forth unless I wait for the gears to slow down, (same time frame as going directly into first) then it easily slips into 1st. I used to drive an old truck without syncronized gears and I don't remember it being this difficult to downshift. What are you guys using for lube in your Spicer's? | ||
| larry currier (Larryc)
Registered Member Username: Larryc Post Number: 99 Registered: 2-2007 Posted From: 64.12.116.203 Rating: N/A |
Bob, some heavier gear oil may help a little. The right way though is to use a clutch brake. Shifting down is not hard. It's alot about always being in the proper gear to begin with. Heres how you have to drive it. Wind it to the governor in first gear, (25mph). Wind it to the gov in second gear,(48mph). Wind it to the gov in 3ed gear,(67 mph), shift to 4th and go as fast as you like. When it pulls into a hill and starts to slow down, shift into 3ed at 70mph by taking the shifter out of 4th, (no clutch) and revving the engine against the governor and holding it there until it falls into 3ed gear. As you use up 3ed gear Watch for 50 or 51mph and when it gets at 51, take it out of gear, speed the engine against the gov and wait for the bus to loose the 2 or 3 mph to reach 48 where it will fall right into gear. The gov will be wound out and you will be able to work the engine thru the whole power band of that gear. When it reaches 27 or 28, its time to go for first so it can drop in at 25mph. Its easy to shift up for everyone. You just take your foot off the pedal and it drops in. Its also easy to downshift you just have to speed the engine up instead of slowing it down! | ||
| John MC9 (John_mc9)
Registered Member Username: John_mc9 Post Number: 323 Registered: 7-2006 Posted From: 66.217.105.215 Rating: N/A |
Bob - I've driven buses like that.... It's a female pregnant dog... If the clutch isn't adjusted properly, it'll be one of those female dogs to downshift. If you're having trouble getting it into first gear at idle (from neutral), and having that much trouble downshifting, then it's a poorly adjusted clutch. Fix that problem first, before you drive yourself crazy trying to fix something that ain't broke. An aside from that? The wet-clutches were always a bear to shift; their "mood" changed with the temperature and usage. Still, a poorly adjusted clutch, added to the inherent problems of a "wet-clutch". The inability to get it into first gear from neutral (at a stop), was the main indicating factor of the need for adjustment.. Call Luke (or any bus operator) for verification... | ||
| niles steckbauer (Niles500)
Registered Member Username: Niles500 Post Number: 732 Registered: 11-2004 Posted From: 72.91.107.56 Rating: N/A |
Nudge the stick (light positive pressure - no grinding) as you adjust the RPM's and it'll slide right in there - syncro or non - HTH | ||
| Bob Wies (Ncbob)
Registered Member Username: Ncbob Post Number: 206 Registered: 2-2006 Posted From: 66.174.93.102 Rating: N/A |
When I first drove my bus I vowed to research this subject to infinity. Lots of opinions but no track records. So I took the bull by the horns, so to speak, and changed the transmission oil to 50# racing oil (available at Advance or Discount Auto Parts)...believing that I'd get better lubricity and smoother shifting. Bear in mind I'm in FL in the winter and NC in the summer so this won't work for everyone. For me..it's made almost a pro out of me in the shifting department. Like my mother used to say, "The dumber the farmer...the bigger the potato". NCbob | ||
| Larry D Baker (Lbaker4106)
Registered Member Username: Lbaker4106 Post Number: 53 Registered: 5-2005 Posted From: 209.153.159.199 Rating: N/A |
You don't say what bus you have. If it is a GM you use 40weight oil in the transmission and once you have it in gear you do not let it set in neutral. If you use the tach. or speedo. to shift you use it to shift down also. I have a 4106 and as I come to a stop I bump into neutral and just before it stops moving I move it into first gear. Adjusting the clutch does not work and they do not have a transmission brake. | ||
| Austin Scott Davis (Zimtok)
Registered Member Username: Zimtok Post Number: 123 Registered: 9-2006 Posted From: 216.37.73.226 Rating: N/A |
Here are a couple things I have noticed: If you are coming to a stop and don't have time to down shift through the gears, push in the clutch but DON"T take it out of gear until you come to a stop. This helps to reduce the "free spinning" of the transmission gears. If you do put it in neutral while coming to a stop without downshifting, release the clutch and let the engine drop to idle speed. Then push in the clutch and put it into gear. After getting into the habit of doing the above, I then started working on downshifting. Because I don't have a tachometer, and my speedometer is not working, I am forced to do it by feel, and trying to judge the speed of the bus visually. Add to these things the fact that my accelerator pedal and cable seem to be sluggish in feel it has truly been an uphill battle in learning how to downshift. There are times that I still miss time the shifting and just have to let the transmission/engine catch up with each other. | ||
| john w. roan (Chessie4905)
Registered Member Username: Chessie4905 Post Number: 555 Registered: 10-2003 Posted From: 71.58.117.21 Rating: N/A |
Bob, I have an 04 like you. The tranny has big heavy gears and takes quite a while to slow down so you can go from neutral to first when the tranny is hot. Fifteen seconds sounds about right. If the idle speed is slightly higher( some have it set up a little higher to have a little better pressure at idle) than spec, it will lengthen to time to slow the gears. You could change the oil in the tranny to new non detergent 50 weight, which I think mine calls for. Might help, but don't start to add oil thickeners, as that trans has an oil pump and it may fail trying to pump thick oil on a colder morning. If the gears never want to completely stop turning, your clutch is probably dragging. What might help is to take tranny apart and reset the bearing preload clearances, which would make the gears slow down quicker. Remember, that trans has a lot of miles and is loose as a goose like the majority of the 04's out there. Maybe a 50 weight synthetic oil would be the ticket as it wouldn't change viscosity as it gets hot. Expensive test at the price of the oil though. I've learned to live with mine, by shifting from the higher gear to first right before I'm completely stopped- goes right in. Hold the clutch in till light changes-I have an air assist clutch. Sometimes I put it in neutral, and get caught with the light changing before I am ready. Best then to shut engine off, slip into gear and restart quickly or if no one is behind you just wait the fifteen seconds, or grind about 5 pounds. They sure shift beautiful when cold, you can really move up the road then. | ||
| Bob Symonds (Bob_symonds)
Registered Member Username: Bob_symonds Post Number: 24 Registered: 5-2006 Posted From: 146.235.66.52 Rating: N/A |
John, MC9, it is a dry clutch, properly adjusted. I'll try the 50 weight oil and see if it makes a difference. Sounds like mine is normal. I just wish the downshifting was easier. | ||
| John MC9 (John_mc9)
Registered Member Username: John_mc9 Post Number: 325 Registered: 7-2006 Posted From: 66.217.106.53 Rating: N/A |
Re: "it is a dry clutch, properly adjusted" After a line run in a bus I rarely used, I was about as disgusted as any driver could get. I had to turn the damned bus off to get it into first gear, after -every- damned time I had to load luggage at a stop. I told the mechanic about it when I got back to the barn.... He said he'd have to adjust the clutch. The next morning, the bus shifted fine, and it was easy to get into first gear from neutral. The depressed clutch is what keeps the engine's power from getting to the transmission and turning the gears. If the gears are turning, the clutch isn't fully disengaging. With a "wet clutch", cold weather can cause the oil to thicken, and propel the transmission gears via engine power even though the clutch may be adjusted near perfect, but the shifting returns to normal when the oil warms up..... With a dry clutch? I'll let you guess at the answer. But... I'll tell ya' one thing.... they didn't design the buses so poorly, as to cause the driver to shut down the engine after each and every stop, just to get it into gear. It's a hazard, it can be dangerous, it'll annoy the hell out of the passengers (and the driver), and it'll cause wear and tear on the AC system and electronics, as well. (the new wave buses designed to turn off during stops are not designed like these old clunkers) If it were my bus, I'd get the clutch adjusted properly. (RJ.... where you at, man? Help this guy!) | ||
| RJ Long (Rjlong)
Registered Member Username: Rjlong Post Number: 1232 Registered: 12-2000 Posted From: 67.181.161.137 Rating: N/A |
Bob - Others have given you good suggestions, let me toss a few your way, too: Craig gave you the link to my article on shifting, that may be of some help after reading and practicing. Gotta have at least a working speedo (GPS?) or tach, tho. . . When you say your 4104's dry clutch is properly adjusted, what do you mean? Did you follow the shop manual and start up front, working your way back as outlined? Or did you simply adjust it in the rear with the handwheel? Big difference. How long has it been since the coach had a new clutch? There are specific settings in the shop manual for the fingers on the pressure plate - get those wrong, and the clutch drags. One thing that hasn't been mentioned, but could, in fact, have a bearing on the challenge you've been facing, is the motor mounts on the bulkhead. If they're allowing excessive movement of the powertrain, it can have weird effects on things. Is the throttle cable operation smooth? How long has it been since it was lubricated? Sticky throttle can be a bother - including holding the engine at too fast an idle when stopped. That alone can have an effect on getting it into gear. IMHO, changing to straight 50wt is overkill. Shop manual calls for engine oil in the transmission on these models. This is one place where you can use a straight 40wt synthetic oil with some improvement - but watch for leaks. How long have you had your coach? That, too, will have a bearing on things, as you learn the idiosyncracies of your chariot. FWIW & HTH. . .  | ||
| Richard Bowyer (Drivingmisslazy)
Registered Member Username: Drivingmisslazy Post Number: 1902 Registered: 1-2001 Posted From: 75.108.83.110 Rating: N/A |
One additional item that has not been mentioned I believe is idle speed. When I first got my 4104 the idle was relatively high but I was not aware of what the correct idle speed should be. An old time mechanic adjusted it down to around 525 rpm and it made a significant difference in shifting ease. Richard | ||
| john w. roan (Chessie4905)
Registered Member Username: Chessie4905 Post Number: 556 Registered: 10-2003 Posted From: 71.58.117.21 Rating: N/A |
Sorry RJ, I thought he was talking about a 4104 like mine which calls for 50 Weight ES oil in my factory manual. Apparantly he has a 4106 like yours that uses engine oil. | ||
| George M. Todd (George_mc6)
Registered Member Username: George_mc6 Post Number: 147 Registered: 8-2006 Posted From: 207.231.81.59 Rating: N/A |
48 MPH in 2nd, 67MPH in 3rd???????? I don't think so...... | ||
| Richard Bowyer (Drivingmisslazy)
Registered Member Username: Drivingmisslazy Post Number: 1903 Registered: 1-2001 Posted From: 75.108.83.110 Rating: N/A |
George, I have to believe he is talking about something other than a 4104, unless it has been extremely hot rodded. As I recall I had trouble getting to 67 in fourth in my 04. LOL Richard | ||
| Buswarrior (Buswarrior)
Registered Member Username: Buswarrior Post Number: 1010 Registered: 12-2000 Posted From: 74.12.88.181 Rating: N/A |
Speedo error? | ||
| George M. Todd (George_mc6)
Registered Member Username: George_mc6 Post Number: 148 Registered: 8-2006 Posted From: 207.231.81.59 Rating: N/A |
Richard, As usual we agree. Thanks again. (My heap will go 53 in 3rd, with 13.5-24.5 tires, after a "clutch smoke throttle start" in first, due to the extremely high rearend.) George (Message edited by George Mc6 on May 18, 2007) | ||
| Gus Causbie (Gusc)
Registered Member Username: Gusc Post Number: 353 Registered: 11-2005 Posted From: 71.112.176.74 Rating: N/A |
My 4104 operation is exactly as Larry says, no matter what combination I try it will not go into first from neutral while stopped and I have completely rebuilt the linkage from front to back with mostly new moving parts. I do disagree with the oil weight though, the 4104 manual clearly says 50wt aircraft quality mineral oil, not engine oil. When I got my 4104 it had 30wt CF-2 oil in the trans so I changed to the 50wt but there was no change in shifting. Just today I took 1.5 more turns on the clutch adjusting wheel and when I first started the bus cold I actually was able to shift to first without stopping the engine. I only moved it a couple of blocks so it remains to be seen if this is a permanent cure. These last 1.5 turns CW left no slack in the clutch arm as per the manual but there are so many other places for slack that this may be what it takes. | ||
| john w. roan (Chessie4905)
Registered Member Username: Chessie4905 Post Number: 560 Registered: 10-2003 Posted From: 71.58.117.21 Rating: N/A |
Gus, check out the rods on the shift tower, the bushings may be shot. It is rebuildable. After unhooking the rods, it can be unbolted from below with a fairly long extension. | ||
| RJ Long (Rjlong)
Registered Member Username: Rjlong Post Number: 1234 Registered: 12-2000 Posted From: 67.181.161.137 Rating: N/A |
John & Gus - You're right, I goofed on the transmission oil for the 4104. Just looked it up in my copy of the shop manual to be sure. Sorry about that. Also checked my 4106 manual, plus one for a 4905, and they both say to use the same oil as in the engine. So GM must have changed the oil requirements when they redesigned the bevel gear system to handle the greater output of the V-8 engine. Thanks for keeping me on my toes, guys!! | ||
| Gus Causbie (Gusc)
Registered Member Username: Gusc Post Number: 356 Registered: 11-2005 Posted From: 71.112.176.74 Rating: N/A |
John, If you mean the thing at the rear, GM calls it a bellcrank, others call it a xmas tree, I replaced all those arms, bushings and pins. If you mean at the gearshift lever I haven't gotten up enough nerve to dig into that mess yet except for the pins and rod ends, both clutch and shift. | ||
| john w. roan (Chessie4905)
Registered Member Username: Chessie4905 Post Number: 563 Registered: 10-2003 Posted From: 71.58.117.21 Rating: N/A |
Sometimes with return springs at the clutch arm and under the driver in that compartment that have been replaced with too stiff of springs, it is hard to tell if you really have play in the clutch or not. you could try to temp. unhook them and see if you have free play or not. Usually the fingers on replacement 04 pressure plates are tack welded, so you can't adjust them in the field.Great that you already have rebuilt the "tree" as it makes a world of difference in the shift lever play.Of course, grease the tower bottom grease fitting at regular intervals. Start pushing the clutch pedal down slowly while someone at the rear watches, and have them yell when the arm moves to see how much play is left in all the linkage pieces. Then see where the arm is actually moving the throwout bearing and not just overcoming the spring pressure to see if you actually took out all the freeplay or not. | ||
| Jim Wilke (Pd41044039)
Registered Member Username: Pd41044039 Post Number: 141 Registered: 2-2001 Posted From: 69.77.144.142 Rating: N/A |
My 4104 shifts fine into first but it takes about 5 seconds. I drive mine just as R.J. Long describes & it works fine. 10, 20 & 50 are the upshift points with my governor set at 2150 and a 3.55 ratio rear axle. To downshift, R.J. teaches that you put her in neutral 5 mph above each shift point as the bus slows, floor the throttle and by then you are at the shift speed & it drops right in. As you learn & experiment with this, you get to where you can downshift at much lower speeds than the shift points. It took me about 5,000 miles to get decent at this. I have a clutch air assist (3" dia x 12" stroke cyl.) and I hold it in first at the lights. There is about 20 lbs foot pressure (measured with a scale!)at the pedal, about the same as my F150. No problem. If your governor is right, the engine should give a nice growl as you gently let out the clutch on flat ground & the bus should just roll right off without any throttle at all. If you are on the flat & you have to rev up or smoke the clutch something is wrong or you are trying to drive this beast like a Corvette. When I got my '04, I had to rev it 'cause the governor & rack was set wrong. And Austin Davis, I watch your bus movies, thanks for those, but your bus sounds like it is idling too fast. They really are very hard to downshift OR get into first if they idle too fast. If they idle too fast, the downshifting method almost won't work. Try to find someone with a photo tach to set the idle. Jim-Bob | ||
| john w. roan (Chessie4905)
Registered Member Username: Chessie4905 Post Number: 564 Registered: 10-2003 Posted From: 71.58.117.21 Rating: N/A |
Some have the idle set higher to make the oil pressure at idle higher, but then you have the clutch issues. BTW, how long will it take to get yours back into gear at a light with a warm transmission if you shift into neutral when you stop. I know that you wouldn't normally do this, but I know that we've all done this once or twice. How many seconds till your gears slow down. Also I had a 1948 ACF Brill with the same transmission behind a gas engine, and it acted exactly the same way. | ||
| RJ Long (Rjlong)
Registered Member Username: Rjlong Post Number: 1238 Registered: 12-2000 Posted From: 67.181.161.137 Rating: N/A |
Back in my charter days, I learned very quickly with the wet-clutch 4905s in our fleet to gently bump the gearshift into 4th, then over to first and away we'd go, after sitting at a light with the clutch out. Became such a habit that I still do it today. Only grumbles for a few seconds, then you're off. Beats shutting it down and restarting. And Jim, thanks for the kind words, they're appreciated. FWIW & HTH. . . (Message edited by rjlong on May 24, 2007) | ||
| john w. roan (Chessie4905)
Registered Member Username: Chessie4905 Post Number: 566 Registered: 10-2003 Posted From: 71.58.117.21 Rating: N/A |
That does not work if you are sitting there in neutral idling and do it to get it into first on an 04. BTW 4905's have countershaft brakes that 04's don't have. | ||
| Don Evans (Doninwa)
Registered Member Username: Doninwa Post Number: 33 Registered: 1-2007 Posted From: 65.61.96.82 Rating: N/A |
John, What causes the countershaft brake to engage? Is it the clutch linkage like in a normal OTR truck or some other mechanism? Thanks | ||
| john w. roan (Chessie4905)
Registered Member Username: Chessie4905 Post Number: 567 Registered: 10-2003 Posted From: 71.58.117.21 Rating: N/A |
I haven't worked on one for 20 years, but I recall that you were cautioned not to push the clutch pedal clear to the floor except to engage first gear from neutral. The clutch discs are small and won't take much abuse; they are mounted on end of countershaft behind an external cover. I believe there were two of them and 3 to 4 inches in diameter. I imagine the clutch pedal depression caused the countershaft to move aft and engage the discs. No lag from neutral to 1st if they are working properly. Wish 4104's had them. Don't know if they were available on 4106's | ||
| RJ Long (Rjlong)
Registered Member Username: Rjlong Post Number: 1239 Registered: 12-2000 Posted From: 67.181.161.137 Rating: N/A |
John - I used that 4th > 1st trick on all the stick shifts in our fleet, both MCIs and GMCs, after learning it. Didn't seem to matter if it was a wet or dry clutch, it just seemed to reduce the grunch going into first. It's my understanding that only the wet-clutch GMs had the countershaft brake. My dry-clutch 4106 doesn't. FWIW & HTH. . . |