Well that was humbling.

[Mex-Busnut]

Thanks for all the contributions.

Ted: Maybe that double stick in video #2 is in fact a 4-wheel-drive transfer case?

[artvonne]

Ted: Maybe that double stick in video #2 is in fact a 4-wheel-drive transfer case?

  No. He is shifting it while moving, and actually saying "first" as he pushes it forward. It looks like an old granny 3 speed with one stick for 1st and reverse, the other for 2nd/3rd. If it was a transfer case lever he wouldnt be doing that.

[gus]

I've driven everything from an 18 wheeler down and have a bunch of antique big trucks but my 4104 is the hardest thing to shift gracefully than anything I've ever driven.

I find that the main thing is giving enough time between shifts, especially going up.

I don't use the clutch going up except when starting from a dead stop, but double clutch (very rapidly while holding down foot throttle) shifting down for grades.

Again, my biggest problem for a year or two was not waiting long enough between shifts going up.

Patience, patience!! I can't say this often enough.

The only thing that will help is practice, videos won't help you much.

[RJ]

You should tackle one of the old GM "Buffalos" with a wet clutch.  You cannot get a smooth or no grind shift without double clutch.

And to make it even more entertaining, try shifting a wet-clutch Buffalo that is equipped with an air throttle!

[bevans6]

I also find the Spicer the hardest transmission to shift that I have ever driven.  I need to get in a rhythm and religiously count the timing until I've been driving for a couple of hours after a long layoff.  Upshifting is one thing, it took thousands of miles for me to get close to smooth on downshifts.  For example the common 4 - 3 downshift going up a hill is very fast, as fast as I can work the clutch.

I have a spare spicer in the shop and I examined it to find out why it's so hard to shift.  The answer is the dogs that engage each gear are very small and there are a lot of them - they are actually the splines that the shift hubs slide on along the main shaft.  the splines are about 1/4" or so wide, and there are around 30 of them.  They have to line up quite precisely in order to allow the hub to engage  the gear.  On most non-synchro transmissions the dogs are separate from the splines, far larger and with a lot more room to engage.  On my racing gearboxes there are often only 4 dogs per gear, and you can engage that in milliseconds.  There is no way to speed up shifting a Spicer 8844, and there is no way I would shift one that I owned without the double-clutch.  The dogs are too small, too prone to wear, and totally  not designed to be shifted without a double clutch.

Brian

[artvonne]

The dogs are too small, too prone to wear, and totally  not designed to be shifted without a double clutch.

Brian

  Are the sliders like common syncro hubs, only solid? Thats how your description sounds.

  Somehow I approached the Bus like a Big boat. The first time I docked a big boat I was amazed at the momentum of so much more mass bumping into the dock. Where a small boat bangs the dock and bounces off, the big boat does not bounce, and rather tries to plow through the dock.

  Everything in the Bus is in greater scale of size to most any other road vehicle save a OTR truck. The bullet bikes can rev in neutral from idle speed to 9K rpm and back to idle, seemingly instantaneously. Vroom vroom. Not so the massive engines and gear trains, which spool up and down so much more slowly. The parts connected to the shift lever and clutch, make up many, many pounds of moving machinery and require much more human effort to push and pull, and so then have much more increased mass and momentum. Start trying to jack the shifts and horse it and it will fight back and make your life hell. Either in making you look like a fool, or emptying your bank account with broken parts. Let it tell you what it wants and go easy, and it seems to answer back much more graciously.

[bevans6]

Art, they are equivalent but not really all that similar.  Inside the gearbox, and inside the synchro boxes that I have worked on, the main shaft change gears rotate freely on the main shaft, and are locked to the main shaft when engaged by a hub that is splined to and can slide along the shaft.  So far, very similar.  On a synchromesh hub there usually is a cone or a baulk ring that acts as a clutch to match the speed of the gear that is being engaged to the speed of the hub that is rotating locked to the main shaft.  After the two gears are matched as the hub is moved, the synchro hub teeth engage into their matching teeth on the gear.  The synchro hub teeth are usually really small, on my gearboxes about 1/8" wide and tall, and there might be 50 of them on the circumference of the hub.

On the Spicer 8844 setup, there is a sliding hub, it just doesn't have the synchro stuff on it, and as mentioned the teeth (what I call "dogs" since that's what we call them on all the other non-synchro transmissions I work on) that engage the gear are actually the splines that the hub is locked to and slides along the main shaft on.  The splines are around 1/4" to 3/8" wide (first and second gear has wider splines than third and fourth gear) and are rounded on their nose to facilitate engaging, but they wear down when they grind (really they are rattling past each other trying to find a speed that matches). 

The one/two sliding hub also has reverse gear on it.  When you flip the solenoid switch to allow reverse gear to be engaged, the solenoid moves the shift rod over so that it no longer controls the one-two  shift hub with reverse gear on it, which is locked in neutral between first  and second gears, and the shift rod moves the reverse idler gear over so that it is engaged between the reverse on the main shaft and the reverse on the layshaft.  Having three gears in the chain instead of two is what reverses the transferred motion.  Reverse is the only gear where an actual gear is moved to make the engagement, and the only gear that is straight-cut.  All the other gears are helical cut on about a 20 degree angle.

Brian

[zimtok]

The first video in ZubZub's post is me.... I'll admit I was just getting the hang of the double clutch thing in the video and I had a tendency to shift too quickly, I do have a bad habit of leaving my foot on the clutch pedal but I don't have any pressure on the pedal. (still no excuse)

It shows the basic beginner how to do a double clutch in a bus, and with all the comments that have been posted explaining the things I did wrong it is a good learning video. Sort of a "learn by MY mistakes" kind of thing. Currently at nearly 150K views if it helps show someone through the double clutching I'm satisfied.

I probably need to do another video with proper technique and also add the downshifting.



.

[gus]

I can't emphasize enough that you don't need the clutch going up in gears once you are rolling. I can do this with all my old trucks, synchro or not.

After seven years of driving the 4107 my opinion is it is just unnecessary clutch wear (Especially double clutching) and the shifts are no smoother than without. You can feel the gears if they aren't ready to mesh, so you just wait.

All that said, I'm sure enjoying my V730!!

[zubzub]

The first video in ZubZub's post is me.... I'll admit I was just getting the hang of the double clutch thing in the video and I had a tendency to shift too quickly, I do have a bad habit of leaving my foot on the clutch pedal but I don't have any pressure on the pedal. (still no excuse)

It shows the basic beginner how to do a double clutch in a bus, and with all the comments that have been posted explaining the things I did wrong it is a good learning video. Sort of a "learn by MY mistakes" kind of thing. Currently at nearly 150K views if it helps show someone through the double clutching I'm satisfied.

I probably need to do another video with proper technique and also add the downshifting.



.

Hey Zimtok your clip  and RJ's article taught me how to double clutch!  I had only heard about but never seen it until I saw that clip.  I never realized how quick the 2 clutch punch could be.  Anyhow I watched that clip and 1 week later drove my bus.  Missed 2 shifts in to 2nd quite pathetically...had to restart from 1st, but the tranny was cold and hadn't been driven in years.  Then I had it.  Don't remember missing again.  FWIW even if your technique is "not right" by some standards it worked for me, but maybe my bus is easy to shift. 

[bevans6]

Gus, did all your old trucks have Spicer 8844 transmissions?  Probably not, but I'm sure the 4107 did.  I'm not saying the transmission can't be shifted without the clutch, I'm just saying that it was not designed to be shifted like that, it doesn't like to be shifted like that and you stand a good chance of breaking it or wearing it  out prematurely if you shift it like that.  Purely based on the design of the engagement mechanism inside the gearbox.   Given that understanding I can't recommend clutchless shifting.  Now, if you can get the thing to shift perfectly every time, more power to you, but mine won't do that.  I don't shift the transmission in my Dodge ram without the clutch either, but i know that it will do it if I ever wanted to try.

Brian

[TedsBUSted]

Hey Zimtok your clip  and RJ's article taught me how to double clutch!  I had only heard about but never seen it until I saw that clip.  I never realized how quick the 2 clutch punch could be.  Anyhow I watched that clip and 1 week later drove my bus. . . .

That's a good point. I wish I had written reply #12 with a more positive tone, because both videos (and of course RJ's article) are very helpful.

Thanks for the  video Zimtok, I apologize for my harsh tone.

Ted

[RJ]

All -

OK, guys, here you go.  I knew if I poked around on YouTube a little I'd find this for you.

Tom McNally from Ohio has a beautifully restored Scenicruiser.  This video was shot on the way back from the Scenicruiser Rally Tom put together along Route 66 in April of 2010. As the video info says, Fred Rayman retired with over 30 years experience driving a bus - and still owns a 4104, IIRC.  Fred does not post on any of the bus boards, but is an avid busnut with an extensive collection of memorabilia.

Watch how easy "Derf" makes double-clutching look:

Fred Rayman drives my Scenicruiser April 10, 2010

(PS: At the 3:45 mark, the fellow sitting on the drivers side wearing glasses is Larry Plachno, the publisher of National Bus Trader and Bus Tours magazines.)

FWIW & HTH. . .

[Mex-Busnut]

By the way, ladies and gentlemen:

My tranny is (according to the original Dina bus factory bill of sale) a Spicer SST-10, for which I have found ZERO information on the web. Can anybody give me some idea what the ten gear ratios might be?

Thanks in advance!

[zubzub]

By the way, ladies and gentlemen:

My tranny is (according to the original Dina bus factory bill of sale) a Spicer SST-10, for which I have found ZERO information on the web. Can anybody give me some idea what the ten gear ratios might be?

Thanks in advance!

http://www.bigtractorparts.com/downloads/Spicer_10spdServiceSM.pdf

I just googled this and found it quickly....if you couldn't find it you may have been invaded by Bing or other invasive mal search engine that pretends to search but directs to sponsor sites