OK, so I'm not a total noob but this is my first coach with a manual transmission (5 speed). I'm a little embarrassed but I can't figure out the trick to not grind these gears. Sometimes I get it right and sometimes I don't.
I get the double clutch concept and I've had lots of manual transmission cars (synchro) but this is different.
When I release the clutch between shifts and put the transmission to neutral, I hit the throttle to raise the rpms and then push clutch in and move shift lever to next gear. Does this sound right? Do I need more rpms at higher wheel/vehicle speeds speeds? I drove this thing 900 miles back from Indiana but it was mostly just chugging along in top gear.
Any advice would be great.
Humbly,
Andy
Blipping the throttle on an upshift is exactly opposite to what you need.
Leave the throttle alone on an upshift.
The driver has to get the engine to approximate the rpm that the engine needs to be at for the gear you are going to.
So on an upshift, the engine will be slower for the next higher gear.
On a downshift, the engine has to be faster for the next lower gear.
Read RJ Long's shifting article at BNO:
http://busnut.com/forum/index.php/topic,3260.0.html
Happy coaching!
Buswarrior
Only on a downshift do you raise the rpms during the double clutch neutral period. Raising the rpms "above" where its smooth to go into the desired gear then keeping just enough pressure on the shift rod for it to find the gear during the rpm drop has always worked better for our 4 speed crash box during a downshift.
Detroit 2 stroke engines fall off very quickly. Which means you have to shift quickly. But don't touch the accelerator on upshift. Takes timing and practice. Course the best solution is an Allison transmission (LOL)! Good Luck, TomC
Best method on a non-synchro is to not use the clutch at all, once you are moving.
Quote from: Lee Bradley on January 30, 2020, 10:33:32 AM
Best method on a non-synchro is to not use the clutch at all, once you are moving.
Not sure that this is correct. I've read that this can lead to excessive wear. Anyone have the facts on this?
His transmission being a late model probably has a clutch brake you push the clutch down to far and it will throw off the shifting big time.I never hurt a transmission shifting without a clutch once rolling a 13 speed Road Ranger would drive you nuts using the clutch for each shift
Quote from: luvrbus on January 30, 2020, 11:26:48 AM
His transmission being a late model probably has a clutch brake you push the clutch down to far and it will throw off the shifting big time.I never hurt a transmission shifting without a clutch once rolling a 13 speed Road Ranger would drive you nuts using the clutch for each shift
Some of the older models had clutch brakes as well - my '74 has one. Just like any heavy vehicle with a clutch brake, the pedal only needs to be depressed far enough to disengage the clutch plates on all shifts while moving, not all the way to the floor. Not only will that screw up shifting, it will ruin the clutch brake.
Ive had LOTS of experience driving standards over the years and, in fact, still drive a manual shift Mini.
But I only drive the bus a few times a year and invariably have a little trouble(i.e. grind some gears)for the first 1/2 hour or so of driving. Most of my problem is double clutching on downshifts as it takes some practice to match the engine speed and trans speed. What happens is I have to attempt the shift once or twice.
The other thing is that when cold the trans shift a lot slower than when hot so you have to adjust to that..
My advice is to "know" the proper way to downshift and then drive it lots.
Where I live it takes a while to get to an open highway and the drive involves lots of stops and some fairly steep hills so by the time I get to an open stretch of highway Ive had enough "practice" that I get the shifts pretty well. In fact, one of the hills I climb I have to downshift from 3rd to 2nd in the middle of the hill which can be a little tricky as the bus is slowing down considerably due to the climb and if you don't get the shift properly it could spell trouble.
Anyway "practice makes perfect"
Not sure on the 5-speed, but on my 4-speed downshifts on an uphill must be started at about 5 mph faster than the desired shift speed. For example, I aim to downshift to 3rd when I get down to 45 mph. I start the downshift at 50 mph, and by the time I'm releasing the clutch pedal the final time I've slowed to about 45 mph.
The one thing that took a while to get used to is just how high the engine must be revved on a downshift. In a car, it's possible to just blip the throttle and downshift. In my GM 4108, I've got to floor the pedal for a second to get the engine speed near governor, and then do the downshift.
If I'm downshifting at a slower point in the curve I don't need to get the engine revved so high, so if I wait a minute and don't start the downshift until the engine starts to lug at about 40mph, I can shift into 3rd with less throttle. But, lugging the engine is not a good thing.
Also, timing on the downshift (and upshift) is key. Like Fred said, slower shifts when cold and faster when warmed up. If I try to put the trans in gear and it doesn't go easily, I let off the shift lever just a tad and try again. Forcing it doesn't usually help.
Last point, panic is a problem. Took me the longest time to get over that feeling of panic if I was having trouble getting the bus in gear. The more panicked you get, the harder it is to shift without grinding. It's hard to not panic when there is a lot of busy traffic all around and people starting to honk behind you, but they'll just have to wait a second or two.
Shifting without the clutch can be done quite well on Roadranger transmissions, but they are synchronized. As long as you avoid the clutch brake (if it works), it can be done on the Spicer going up, but doing going down is a little trickier. Read R. J. Long's article and every comment here, and then practice, practice. Sticking to higher gears will lug the engine and cause damage. If you hear light grinding, it will survive that, but if you try to force it and hear clunking, well, there goes a tooth bit. It is an art form shifting the Spicer, it is also a great anti-theft deterrent because the current generation probably won't get out of first.
I have the five speed in a 1982 Eagle that I drove through city traffic after it had been sitting for twelve years. The linkage was a little stiff, but it worked fine. You feel more connected to the bus with the manual, you can feel the vibrations and the forces down below. The only catch is your left leg gets a workout if you use it. The five speed is much handier to have than the four speed, so be thankful your bus came with it. The five speed is also wider than the four, and switching to an automatic or a Roadranger 10 speed would be easier space wise.
Quote from: DoubleEagle on January 30, 2020, 01:25:42 PM
It is an art form shifting the Spicer, it is also a great anti-theft deterrent because the current generation probably won't get out of first.
Hey! ???
The current generation probably couldn't GET it into first.😋
Well, I'm glad I asked!!
Very helpful information.
No wonder my downshifts were fine but my upshifts were not - I was raising the engine speed between upshifts!
I know I've got to practice but I tend to agree with many if you, there is a certain connectedness and satisfaction with driving this thing. I'm not sure its better than an automatic but it certainly is more engaging. ;D
Now i have to look into this clutch brake thing. I have been pushing the clutch to the floor for all shifts. But, thinking back on it, there is a definite change in pedal feel about halfway through the stroke. Could that be what I'm feeling?
Quote from: AndyinCT on January 30, 2020, 06:19:13 PM
...Now i have to look into this clutch brake thing. I have been pushing the clutch to the floor for all shifts. But, thinking back on it, there is a definite change in pedal feel about halfway through the stroke. Could that be what I'm feeling?
There should be a small amount of free play at the top of the pedal travel. Then the pedal with disengage the clutch. Clutch brake should be the very last little bit of travel. On mine the pedal needs to be all the way to the floor. The semi I've been training in has a clutch brake which engages about 1/2" from floor. Can't feel the clutch brake in the pedal at all, but when it's not engaged it's really tough to get into first.
Quote from: AndyinCT on January 30, 2020, 06:19:13 PM
Now i have to look into this clutch brake thing. I have been pushing the clutch to the floor for all shifts. But, thinking back on it, there is a definite change in pedal feel about halfway through the stroke. Could that be what I'm feeling?
You should only be pressing the clutch far enough to break torque unless you're starting up from a dead stop. Personally I prefer to shift without the clutch where possible but I've run into transmissions where I still need to break torque with the clutch. If you're upshifting without the clutch what happens is you slip it out of gear in the moment between when its still pulling in the lower gear and when the engine RPMs drop far enough to start to slow the vehicle. There's a moment there where there's no torque on the transmission and it will just fall out of gear. Then you want to hold the shift like you'd hold a ripe peach - just barely touching it. You "float" the shift against the new gate and wait until it falls into the higher gear. If you do it right there'll be no noise and you'll never have to exert any measurable pressure. If you have to fight it you're doing it wrong. Coming down its the same principle except that you have to put a little throttle on to release the torque before coming out of the higher gear and then rev up as you float against the lower gate. I usually prefer the clutch on a downshift. I was trained to double clutch and I can't stop my leg from doing the double stab whenever I use it which is partly why I prefer a clutchless shift on the way up.
Ultimately there's no substitute for making about 3 or 400 shifts to get it right. Some engines drop RPMs faster than others. I've seen guys who used the Jakes to get the engine to drop faster so they could upshift quicker but that's never worked for me.
That's gold right there, bob. I can't wait to go try this out! Luckily I live in a rural area where I can just go out and play with a bus around town.
I grew up not too far North of you, so I suspect you have a few hills to go up and down. It would be very useful to master downshifts all the way down, it will come in handy.
On out 4104, you always had to make the first few shifts about twice as fast when cold.
Something else I thought of overnight. When you're learning start by always driving it until the engine hits the governor before you make a shift. Watch the tach immediately after the shift so you know what your RPM drop is. That will also be your RPM increase when you are downshifting.
Dad was a trucking contractor hauling oil field supplies from Houston to Alaska all his trucks were 5 speed with a four speed auxiliary,first time I saw a truck with one transmission shift lever I thought something was missing, the 5x4 were a challenge for awhile shifting 2 levers at 1 time, you will be fine just take your time forcing the issues just adds to the frustration
Quote from: bobofthenorth on January 31, 2020, 04:36:14 AM
Something else I thought of overnight. When you're learning start by always driving it until the engine hits the governor before you make a shift. Watch the tach immediately after the shift so you know what your RPM drop is. That will also be your RPM increase when you are downshifting.
I like this idea but I don't have a tach. I have been running it up to the governor, if I don't and i'm on any sort of uphill grade, she doesn't like it...
Quote from: luvrbus on January 31, 2020, 05:03:04 AM
Dad was a trucking contractor hauling oil field supplies from Houston to Alaska all his trucks were 5 speed with a four speed auxiliary,first time I saw a truck with one transmission shift lever I thought something was missing, the 5x4 were a challenge for awhile shifting 2 levers at 1 time, you will be fine just take your time forcing the issues just adds to the frustration
That sounds like the Mack Quadraplex. You can't afford to daydream while driving them or the Triplex and loose track of where you are at (at least in my case). :o
When I was a little kid, Dad bought and converted a 46 Chevy school bus. 217 cu. in. 4 speed transmission. He added a three speed auxilliary which helped on the hills. I watched him sometimes shifting with one arm through the steering wheel moving both shift levers going from third underdrive to second overdrive with no grinding. He drove tractor trailer during WW II. We travelled all over the US one summer and several trips to the keys at Christmas time. I still recall the gear whine when watching The Grapes of Wrath movie.
Quote from: AndyinCT on January 31, 2020, 06:29:38 AMI like this idea but I don't have a tach. I have been running it up to the governor, if I don't and i'm on any sort of uphill grade, she doesn't like it...
No tach makes it more difficult but all the more reason to drive it until it hits the governor. At least that way you've got one known quantity.
Goin out tomorrow morning to try this the right way! Will report back. Thank you very much for all the tips and input.
Ok, I'm getting better. I think I have the process down now.
Bring it up to the governor, clutch in, shift to neutral, clutch out, gently "feel" the speed difference of the gears and once its matched, clutch in, shift to next gear, clutch out, throttle up.
Sound right? I'm not grinding much at all it just takes practice and understanding. Quite a little skill there. Much appreciated!
It absolutely will get easier. A tach is a huge help but as you have already figured out, not essential.
Good news.
I find that sometimes it helps to put a little 'stutter' in the lever just as I'm putting it in gear, if it gives any indication that it's not quite ready. By 'stutter' I mean I let off pressure ever so slightly, then try again to go in gear. Seemed to help reduce my noise making considerably.
Do you have an air throttle? I do, and I found that it affected my timing somewhat until I got used to the different way the engine responds to it as compared to a traditional throttle.
Check the specs for your transmission.
Lots and lots of buses do NOT have a clutch brake.
The trick to catch spinning gear sets in a non-clutch brake transmission, or one in which the clutch brake has been burned out of it...
The transmission will go into a higher gear more easily, and with less noise, then slip it back to first. So, 3rd or 4th in a bus transmission.
The other trick is not to let the gearsets get spinning that fast. Leave the clutch engaged when coming to a stop until the engine speed is just nudging idle, clutch in, bus stops, slip into 1st, no noise.
Happy coaching!
Buswarrior
Once you get the hang of it, shifting a Spicer without the clutch is easier than doing it with. I was forced to learn when our clutch went out. I drove from Joshua Tree to Bakersfield only using the clutch to get into first. Knowing the right rpm to shift at is the thing. For me, having a tach was essential. Once the transmission and engine speeds were coordinated it would just slip into the next gear. You could sort of feel where the right space was.
The trip to Bakersfield was the last time I did it though, since I left with the Allison Don F installed. Definitely one of those "never-looked-back" experiences.
Andy, you should be able to skip a step or two in your upshifts. If you keep the clutch in when feeling for the next gear you should be able to feel when it wants to go, pop it in and declutch. So you are only pushing in the pedal once.
On your downshifts, without a tach the idea is to let the clutch out in neutral, bring up the engine speed to rev match for the next lower gear, which again with a light touch you should be able to feel. You may go past it and you can catch it either going up or down in revs. Anyway as mentioned by Lin, depending on how well your transmission and you like it, when you feel that little give you may be able to just pop it into gear. If it feels too jerky a light touch on the clutch can soften it. Or you can rev past it, depress the clutch, and catch it as the revs come back down.
Jim
I dunno if this has been already addressed. Crawl around and over your Bus Conversion and see if there are any, (or many) lube or grease points on the shifter linkage. Rub points. Grease zerts. Worn out parts.
An easy way to check for this before crawling is to start the Bus and place the shifter in neutral. Safety first. Place in the various gears. Does the shifter move easily? Like a thumb and only one finger finger easy.
Some shift rods, (pipes) have many many zerts and a few small U-joints. A very stiff shift linkage can make smooth shifts nearly impossible. Once your linkage is lubed it is easy to learn to shift your five speed.
Spicer or Fuller? That I dunno.