RJ Long

[Red Rider]

Most of us on this board have seen all kinds of information from RJ over the last few years however I was blessed to have his famous article regarding the shifting of a Spicer four speed trans, demonstrated and in person. RJ attended our Quartzsite Rally last week and I got into a discussion with him regarding a problem I was having shifting into 2nd gear when the drive train was cold. Well bright and early the next morning RJ was standing at my door and planning to go for a ride to see if he could figure out why only trouble with one gear and then only when starting out. After a 1/4 mile and a 1/4 pound of gear grinding RJ asked to drive. It turns out that when I left home I was continually short shifting from first to second which is required only one time before being warmed up. It seems that warming up had nothing to do with it. I now Know that its all timing and feel as well as"forget the tach".

I thank RJ not only for his knowledge but his time. I figure somebody who drove 500 miles to a rally with approx 80 Coaches would have better things to do than drive an 06 out in the desert.

Thank you so much RJ.

[Oonrahnjay]

...    Thank you so much RJ. 

      Not the first or only time.  Many people have similar stories.  He's a great asset to the converted coach community.

[HB of CJ]

When at about +25F our old RTO910 Fuller Roadranger 10 speed shifted sosss fast.  For about the first 5 miles, the 90 weight gear oil was so cold and thick, shifting the tranny FAST enough was almost impossible.  Our solution was to stab double clutch and move the shifter as fast as we could, particularly when up shifting in the low side.

When very hot and the gear oil had a chance to heat up to about 150F, the shifting technique became the opposite, particularly in the high side.  Then you had to wait a bit and full double clutch when up shifting.  The 855 SC Cummins when hot tended to lose rpm with no throttle quite slowly.  Slowed things down.  One quickly got used to it.

[RJ]

Thank YOU, Mike, for your kind words, they're appreciated, as are yours, too, Bruce.

For those who are interested, the problem Mike was having basically boiled down to the gear ratio split between 1st and 2nd in the transmission, and thus trying to do something that the engine wouldn't let him - regardless of whether it was cold or hot.

There is just slightly under a 1,000 rpm split between 1st & 2nd in his GMC (like most GM 4-spds).  Mike was trying to upshift around 1300-1400 rpm, watching the tach like a hawk searching for lunch. With the normal engine idle at 550-600, you can easliy see why Mike was having problems if you do a little number crunching.

Mike graciously let me have a go in the saddle so that I might experience the problem he was dealing with.  I warned him in advance that I was a little out of practice, as it has been over 20 years since I drove a manual gearbox coach, but he let me drive anyway (albeit with a worried look on his face!) 

After a few minutes of working the clutch to determine the take-up point,^* off we went.  My first 1-2 shift I bumped it a little going into 2nd, so I stopped and tried again.  Second time it fell into gear just like it's supposed to, and Mike's jaw dropped, with a "how did you do that?" expression on his face.

How did I do it?  Simple: I ran the engine up to the governor (2100 rpm) before shifting, which gives the transmission the cushion it needs for you to synchronize it while the engine rpm is falling off, especially on this particular shift.

When Mike got back behind the wheel, he was elated the first time he tried it "my way" and it easily dropped right into 2nd.  After practicing for a bit, he got better and better, and even began to recognize when he was rushing the shift and the transmission complained to him about it.

Now all he has to do is set that Styrofoam cup filled with water on the dash and practice smoothing out his shifting so that he doesn't spill the water with his clutch work!

To wrap things up, Mike also got his mirrors adjusted properly, too!  Plus, as an added bonus, Dan West is going to make up a couple of brackets for him so that he can mount a convex (fish eye) mirror to reduce the blind spots.

Oh, and don't tell Mike, but it was fun to get behind the wheel of the Sports Car of Buses again!!   

FWIW & HTH. . .



^* Mike's clutch is slightly out of adjustment, he doesn't have enough free play at the pedal, it needs to be backed off a little as the take-up point is too high.

[HB of CJ]

The gears are so close together: 22%, 26% and a 28.5% range shift split, all one had to do to "progressively" up shift was to start out in second gear revving the engine up to only 1000 rpm or so then quickly up shifting to the next higher gear.  This only worked if one used every gear and quickly "climbed the ladder".

Each higher road gear speed let one slightly increase the rpm before up shifting.  Usually we just used our ears.  About 1000 rpm, then 1100, then 1200, then 1300 and so forth.  Before you knew it, you were up to highway speed.  Tenth gear was only used at and above 60 mph which was 1500 rpm.  Tall gears indeed.  Worked OK.

[buswarrior]

RJ is the real deal.

With a coach transmission and only 4 or 5 gears in the older stuff, best to never mind the concept of "progressive shifting"...that's for the rare few busnuts with 9/10/13/15/18 speed transmissions.

There is no power in the lower RPM in a Detroit 2 stroke, and with those few gears, the big RPM spread between gears dictates a fairly narrow window of opportunity, or overlap, in gears and road speed.

In other words, for a given road speed, you have no choice, it belongs in that certain gear. Period.

Your shift points may be best considered set in stone, in relation to governed engine speed.

Going up, shift it just before the governor interferes with engine power.

Going down, start the shift process at just a little faster road speed than going up, by the time you get done, you'll be in the power.

Good Grief, RJ, 20 years...?  We're all getting further from our youth at an alarming rate....

happy coaching!
buswarrior

[Scott & Heather]

And this is why I'm on this forum daily. I have two automatic coaches so none of this applies to me, but it's so so interesting to read you guys banter on stuff like this. Fascinating and fun. You guys are a wealth of knowledge. And thanks for the 3am entertainment


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[Bill Gerrie]

Thanks for the trip down memory lane RJ. It was in the late 60's I drove a standard transmission bus. I was used at Gray Coach in the summer and we drove the Greyhound from Buffalo to Toronto and from Toronto to North Bay or Sudbury. Also some Ontario Northland coaches. Back then to go north they only used standard transmission coaches. I remember there was quit a difference in the speed of the shift between the GM's and the MCI's. You are right Buswarior. Time is flying by.   

[TomC]

Progressive shifting only works on a 9, 10, 13, 15, 18 spd transmission. Buses purposely had only 4spd to let the drivers shift without thinking-rev to governor and shift, rev to governor and shift, rev to governor and shift-then you were at freeway speed. Downshift at the same shift points. When that stopped working, automatics were introduced. Good Luck, TomC

[Red Rider]

Clutch  has been adjusted and really works well. Thanks again.

[lvmci]

2nd RJs  great contributions to the board, tom., lvmci...