Any tips on shifting this thing?!

bobofthenorth · January 30, 2020, 06:37:44 PM

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.

AndyinCT · January 30, 2020, 06:48:17 PM

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.

DoubleEagle · January 30, 2020, 08:44:52 PM

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.

chessie4905 · January 31, 2020, 03:56:58 AM

On out 4104, you always had to make the first few shifts about twice as fast when cold.

bobofthenorth · 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.

luvrbus · 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

AndyinCT · January 31, 2020, 06:29:38 AM

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...

DoubleEagle · January 31, 2020, 07:23:51 AM

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).

chessie4905 · January 31, 2020, 08:16:41 AM

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.

bobofthenorth · January 31, 2020, 02:48:21 PM

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.

AndyinCT · January 31, 2020, 03:25:29 PM

Goin out tomorrow morning to try this the right way! Will report back. Thank you very much for all the tips and input.

AndyinCT · February 03, 2020, 04:11:36 PM

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!

bobofthenorth · February 03, 2020, 05:12:46 PM

It absolutely will get easier. A tach is a huge help but as you have already figured out, not essential.

richard5933 · February 03, 2020, 05:23:06 PM

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.

buswarrior · February 04, 2020, 05:48:31 AM

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