Hey guys, Most of you know the 4107 4 speeds were known for grinding gears. Even when you read the history, drivers were even sometime embarrassed that passengers had to hear the grinding. When I drive, there is a good bit on grinding, sometimes even hard to get into gear, I feel like there could be a lot less grinding if I were given some pointers. I've driven a stick all my life in my car. Sometimes double clutching helps but sometimes it doesn't. I have really found my groove yet... any suggestions? ;D
4107's grind going into 1st so shift into 1st before starting and shift into 1st as you slow down just before it comes to a stop will stop most 1st gear grinding. You must shift all other gears with double clutching. Time your shifting with governor and most grinding will stop.
My 4107 is AT but my 4104 is manual.
I shift up without using the clutch, the secret is having patience - it just takes a little pause while in N.
Down I always double clutch very fast on a hill, level I don't use the clutch.
I agree about being in 1st before starting!
I also try to shift into 1st right before stopping if I'm continuing on. It is much easier to go to 1st when barely moving.
The pause of patience is the key! wind up and clutch out of gear clutch up and down and .... shift. RJ has a real cool lesson on shifting if not here for sure on Busnuts website under articles. Good luck. shift slower!
Find and read RJ article on shifting ---it is ALL in the timing -between double clutching -- and engine rpms. From 1st to 4th is all in double clutching and timing .....to down shift from 4th to 3rd or even 2nd requires a raise in rpms and here again timing- practice make every thing better. And like said before JUST as you quit rolling for a stop EASE er in 1st you will be good to go
Bryan -
http://busnut.com/forum/index.php?action=articles;sa=view;article=41 (http://busnut.com/forum/index.php?action=articles;sa=view;article=41)
Give me a day with you and I'll have you shifting like a "real" bus driver - not like today's "stab n steer" jockeys who cannot even manually shift an automatic properly.
But try the above first!
FWIW & HTH. . .
;)
He will want to read VERY carefully and thank you for the link He should be able to get er done now
We spent the money and flew RJ out to give us driving lessons. Granted we have an automatic (oops - not manual) tranny but it was still worth every penny and we learned a ton. So many things we had no idea about. It will certainly change the way you approach driving a bus. He also drove our bus like a sports car. I never knew my bus could drive like that.
-Sean
Fulltiming somewhere in the USA
1984 Eagle 10S
www.herdofturtles.org (http://www.herdofturtles.org)
Bryan if you need me to give you some pointers on shifting (I have done a bunch of it ) just give me a call and I'll drive over, check clutch adj.and we will take it for a drive and I'll show what you need to know .
I only double clutch when down shifting. I drive truck for a living but I will try to describe this in the best way possible.
So you start the vehicle and if you haven't moved anywhere, you can probably slide it in and out of gear.
Basically there are two spots in these transmissions. You have a High rev shift and low rev/idle shift. And it is all about matching throttle response/RPMs/speed to the matching gear.
Think of the gears having two speeds.
Low 1st (idle speed), High 1st(pedal to the floor wound out speed), slide out of gear, Low2nd gear (close to idle/low rev speed and as you hit the gas) High 2nd (pedal to the floor), slide out of gear, Low 3rd and you missed you can flutter the gas pedal just around the idle/low rev speed until you can slip it into gear, Wind it out, High 3rd gear, slide it out of gear, low forth gear, wind it out high 4th so on and so forth . None of the shifting has been done with the clutch depressed. You might be able to even shift through you
This is all done with syncing your engine speed to your transmission input shaft speed (or something like that). If you want to practice on something cheaper you can actually drive a standard car by timing your shifts.
Play with that gas pedal a little more and hopefully that will get you shifting a lot smoother. In a truck it is easier to hear how the gears are grinding. In the bus you are going to have to feel it more. And by that is a buzz saw that I am trying to force the that gear through or does it feel more like fitting a key in a key hole at night? Lol Analogy central!
When I first started driving when I came up to a stop light I dreaded when it would turn green if I wasn't at a complete stop. No need to panic! Just take it easy and see if you guessed the right gear to slide into. Lol otherwise take advantage of first in you are just hanging out in the middle of the road.
Good luck :-)
wdtjawshwdt -
Nice commentary for a newbie! Glad to see others pitching in to help.
Your thoughts, tho, did bring up a question that will help you understand what Bryan's up against: Does your truck have a wet clutch? Whole different animal when it comes to putting it in gear at a dead stop. Plus they shift quite differently between cold and hot.
The 4-spd transmission in Bryan's 4107 has HUGE gaps between each gear, something that drives truckers totally crazy until they figure it out, then it frustrates them to no end because there aren't more gears!
rgrauto -
Good suggestion about adjusting the clutch before a driving lesson, in addition to volunteering to give Bryan a hand. Just be aware that proper clutch adjustment on a GMC starts in the exterior compartment underneath the driver and you work your way back from there. Quite different than an MCI.
Seangie -
Thank you for your kind words, they're appreciated! (Oh, and since when did you take out the automatic and install a manual gearbox? Was that one of those conversion projects that didn't make it to the blog? Hehehehehe. . . )
Bryan -
Let me know if you can't open the link in my previous post. I'll send you the article in .pdf format.
FWIW & HTH. . .
;)
I knew this was the place to come to learn how to drive! haha! Thank you everyone for your input...
RJ, I can't read the article because for some reason I still haven't been approved for busnut.com. I registered a long time ago. I submitted under a new username tonight, so maybe this one will go thru. My username is "bshoc" if you know someone over there that can approve it.
Glenn, I've been meaning to catch up with you on the phone. I would love to take you up on your offer! I will definitely give you a call soon.
Again, thank everyone for being so helpful.
RJ, I'd love the article! my email is email@b-shoc.com
I have an MC9 and it seems like I should just stand on the gas and shift. And it is a different beast compared to truck. But when I drove the MCI for the first time it felt like the first time driving truck. Shift points were just a little different. My timing was all off the first couple hours of driving it but it started coming together.
I have faith in you Bryan...hopefully your transmission does too. :-p
Bryan, I drove and instructed on 4903's (big 4107's) and 4905's (long 4108's) in service. We always double clutched, going up and down. Always blip the throttle on downshifts. (Clutch in, out of gear, rev engine, clutch in, ease into lower gear.) As stated earlier, you're trying to match the revs of shafts & gears. Always ease into first before coming to a complete stop. Some coaches would go into first at a stop, most would not. Here's the point. Every coach shifts differently, you have to learn (listen) to what your coach wants to do -- cold and hot, uphill and downhill.
That's what I taught, and what I did (mostly). On coaches I was familiar with, I'd go up without the clutch occasionally - just for the heck of it. I don't remember, but probably tried it going down, too. I was decades younger then. Now, if I were paying for any damage, I wouldn't do it. If I were managing an operation again and caught one of my drivers doing that, it'd be time off for bad behavior.
One fishbowl we had (4104 transmission) shifted so fast that the driver risked arm injury. Even two sister buses, with consecutive serial numbers -- shifted differently. I recall that I couldn't blow a shift in 246, but 248 - both 4905's was an average coach -- make most shifts, but blow one occasionally. (Our coaches all had even numbers, owner's son had been killed in an odd-numbered coach, and he would never have an odd-numbered coach again).
The first year we had air-throttle buses, 4905's 252 & 254, I never could shift the darned things. Engine revs would die down too quickly. Other drivers could handle them, but I hated those buses. I'd never take one out to instruct, since I couldn't shift the darned things to my satisfaction.
Arthur
Rj. Thanks for the heads-up on the Gm. clutch adj. I owned a 4104 before the MCI but that has been a while ago. Bryan if you need some help message or give me a call ,Y'all have a good day.
Hi Bryan, everyone above has given you great advice. In my off and on career as a bus/truck driver. I have driven GMs, Eagles, MCIs and Prevosts. The only constant is that they all have a different feel. You will find your coach's personality and then enjoy. Just remember how big you are and how long it takes you to stop ( I call it situational awareness ). Shifting will come in time but is not the most critical. Take you time and have fun.
--Mike
Sent from my iPad using Tapatalk
With only 4 speeds, the buses were designed to rev to governor then shift. Since no tachometer, you shifted by speedometer. Make note of shift points, possibly putting a small arrow at each shift point on the speedometer. Rev to the governor and then shift-double clutching-think of it as first shifting into neutral then shifting into the next gear depressing the clutch each time. Part of the reason Detroit 2 strokes worked so well is that they fell down to idle very fast compared to a 4 stroke engine-hence could shift very fast.
The best way to master a manual is to switch to an Allison automatic. And this from myself that was a cross country truck driver for 21 years and 1.3 million miles on 13spd transmissions. Once you experience the performance and ease of driving an Allison, you'll never go back to a manual. Good Luck, TomC
All good advice above, except I don't recommend shifting without the clutch. When you miss a shift, you will break expensive parts in the transmission. The bus was engineered with a clutch, use it.
Always felt once you got the feel of the setup, using a clutch for anything but starting or stopping was immoral ;D
Dave M
I posted these photos recently, but this time to illustrate the tiny dogs that engage the splines in the shift hubs in the Spicer 8844. This one is an in-line but the boxes are about the same internally. You can see the tiny dogs, about 1/4" wide and tall, at the base of the gears. They are identical to the splines on the main shaft that the shift hubs slide along. There is almost no play between the internal spline and the dogs on the gears where they engage. You can also see the rounded, almost pointed, face where the hub slides over the dogs to engage it. That is what is rattling or grinding when you miss a shift. Gearboxes that are designed to shift without a clutch have very large dogs and far fewer of them, and there is a lot of space between them so when you unload the box it slips out of gear and then the large dogs can almost fall into place on the next gear. This Spicer ain't like that. Sure you can shift it without a clutch, but these photos show exactly why that is a dumb idea. It just isn't designed for it. It was designed to be strong and cheap. Those tiny little dogs can transfer immense torque and last a very long time - if a poor operator doesn't chip off a dog and ruin the gear.
Edit: the bottom picture is a closeup of the splines on the main shaft and the dogs on the gear. You can clearly see the sharp, square profile of the splines that the shift hub (in this case the shift hub is also reverse gear) slides along, and over the dogs with the very worn, rounded noses that are on second gear. They are each about 1/4" wide and are a very good fit, there is almost no slop at all between the shift hub and the gear once it is engaged.
Two things to add -- the advice from RJ and others is spot on, however there are a couple of things That help putting it into practice.
First, the gearbox and drivetrain do 'talk' to you through your fingers as long as you do not grab the shift lever in a death grip. You might think of it as being like tickling fish (without the wet and slimy part) if that helps.
Second, every part of the drivetrain is subject to it's own inertia. Matching the relative motion (RJ's count during shifts) can't be sped up without making embarassing and potentially expensive noises. This makes it especially important to 'drive ahead' anticipating road and traffic changes before they become necessary. Don't be an emergency looking for a place to happen.
e3
I drove truck before I got this bus and own two heavies now. You can forget 90% of truck shifting experience with this 4-sp, hardest thing to shift I ever drove!! I attribute this to the long linkage, just my guess.
Many trucks have clutch brakes, this does not, whole new ball game!
Shifting without a clutch is no more harmful than with, a missed shift is a missed shift either way. There is no difference in gear raking either.
I've been doing it for years with no problems. Actually it saves wear and tear on the linkage!!
Quote from: TomC on March 19, 2014, 08:20:48 AM
The best way to master a manual is to switch to an Allison automatic. And this from myself that was a cross country truck driver for 21 years and 1.3 million miles on 13spd transmissions. Once you experience the performance and ease of driving an Allison, you'll never go back to a manual. Good Luck, TomC
LOL, could not agree more. I like to enjoy the trip, not get there dripping sweat.
Quote from: lostagain on March 19, 2014, 11:44:31 AM
All good advice above, except I don't recommend shifting without the clutch. When you miss a shift, you will break expensive parts in the transmission. The bus was engineered with a clutch, use it.
Most good tranny shops can tell when rebuilding a tranny if the driver was shifting without a clutch or not. Most companies frown on this practice because they know what maintenance costs.
Some times you just have to laugh, a good friend who can do anything, welds look computer done, really can do anything EXCEPT shift gears, some where between the clutch, throttle and gear shift, everything goes out the window ;D A great guy, just this hangup with a gear shift. Everyone still laughs about it. You have to see the humor in this.
Dave M
No clear answers on "slip shifting" or "double clutching" in trucker forums. Do what works Bryan. Haha. The biggest thing is syncing your transmission with the engine.
I have only gotten to run my MCI on one long run and I have to agree that the temp of the transmission does make a difference. From what I remember I did end up double clutching when I took all my buddies on a bar tour because it just wasn't slipping as easy.
I have just become a lazy truck driver and don't like my left leg getting too tired.
..+ 1.. ;D...George...ps look for the left leg limp ;)
Quote from: Runcutter on March 19, 2014, 06:13:13 AM
The first year we had air-throttle buses, 4905's 252 & 254, I never could shift the darned things. Engine revs would die down too quickly. Other drivers could handle them, but I hated those buses. I'd never take one out to instruct, since I couldn't shift the darned things to my satisfaction.
Arthur -Wet clutch air throttles were fun, weren't they! ;D
Quote from: TomC on March 19, 2014, 08:20:48 AM
The best way to master a manual is to switch to an Allison automatic.
Good one, Tom! :D
Bryan -The best way to learn is to practice. Then practice some more. It will take awhile to learn your coach's "feel," but once you get it, you'll be good to go forever - like riding a bicycle.
FWIW & HTH. . .
;)
Here's a comparison picture of the sliding synchronizer on a 10spd Roadranger transmission. You can see by the thickness and gapes between that these transmissions are made to be shifted without clutch. Good Luck, TomC
And as compared to the 4spd that has a colar that slides over the gear to engage, the Roadranger has the shift fork that sits in the middle of the slider pictured and that slides into the gear-much more robust for misuse. So when shifting the 4spd, always use the clutch.
We can also tell on a fully synchronized 6spd trans when the driver has not been using the clutch. How? The synchronizers are worn out by 80,000miles and you get gear grinding. Wheras with a driver that always uses the clutch, the synchronizers should last 3-400,000miles-or the life of the transmission before overhaul. Good Luck, TomC