What is a 5&2 Transmission?

[TyYota]

I'm new, and not a truck driver but I have a couple questions about BIG truck transmissions.
I know that a modern 10 speed tranny used a 5 speed (shifted twice) with a split between 5th and 6th. How does this differ from an old 5&2?
Is a 5&2 a 5 speed with a under/over drive auxillary tranny (with a spit in each gear)?
How are the auxillary transmissions shifted (I know the old ones had two shifters, but did they ever use air or hydraulic shifters (with toggle switches)?
With a 5&3 or 5&4, wouldn't some of the ratios become redundant (4 hi, and 5 lo are too close or overlaping even)?
Is a truck with a two speed rear axle refered to as a 5&2?
Thanks for you help!
Tyler

[W. Lineman]

Ah yes, the Duplex.

Short answers are yes, yes, no, yes, no,  but I almost think the questioner already knew that, he seems very perceptive.

I remember when as a kid I stood on the fuel tank, looking in to an old Brockway coal truck that had two sticks.  I was mesmerized with the shift labels, a five speed and a four speed. Little did I know how much I'd be grabbing 'em later on.

Two transmissions was no new concept, I knew a guy who had restored a 1916 Ford Model T that had a Ruxtell truck conversion. He called it 'Sweet 16". It had, in addition to Henry Ford's two-speed push-pedal planetary gearbox, a four-speed auxiliary and a two speed rear axle. So it had 16 possible forward speeds. Although I doubt they were all shiftable.

Not too awful long ago a friend had a B-67 hobby truck. That was a B-61 single axle Mack with the concave panel on the back of a cab for pulling a 40 foot trailer inside 50 feet when that was the biggest allowed.

Well his regular truck was an International ball hitch truch as he was a mobile home toter. But times got slow and they had no work, but if you had a fifth wheel tractor, well they still had work pulling two Econoline campers on a trailer. So he put the hobby truck on the road for a few months which turned into over three years. He even put a ball on it when that work came back.

The Duplex finally wore out  and he was looking at a big bill and I said why don't you find a Quadroplex from one of these old junk coal trucks we got all around, so he did. Now there was a mobile home toter, with 20 forward speeds. Two overdrives where he had had none, it would fly, and the low hole helped him place the homes.

[RodeoJoe]

Ah, yes, the old two and three stickers.......  Learned to drive on a 4 x 4 and drove lots of 5 x 4's.  Some of those old 5 x 4s were terrific, specially if both of 'em were overdrives.  Those older engines would run out of horsepower before you ran out of mph.  Put both trans in low gear and you could pull stumps, put 'em both in overdrive and you could scare the pants of yourself.  S'funny, if a truck shows up with 2 sticks in it a lot of the younger fellers want to know what the second lever is for.

[TyYota]

Thanks guys.
Lineman I'm a little unclear of your answers: you answered yes, yes, no, yes, no (5 answers) but I think I only asked 4 yes/no questions. Can you clear this up I'm not sure if there was ever an air/hydraulic shifted "brownie" and such.
Thanks
Tyler

[RodeoJoe]

Yes TyYota, there is an air shifted A box out there.  Years ago I drove a Ford Louisville with an 8V71 screamer with a Spicer 5 speed that had a 4 speed auxiliary that was air shifted with a flipper switch mounted on the main stick.  A few years later I had a lowbed business and the truck that my partner drove was a Mack Superliner with a KT450 Cummins, 15 speed Roadranger with a 4 speed Spicer auxiliary that was also air shifted.  I don't recall having any trans trouble with either setup but that KT450 was a PITA.

[Rob Archer]

Our panel of expert experienced truckers please.......


It was often found in straight trucks , and was often heard grinding.
1 LO
1 HI

2 LO
2 HI

3 LO
3 HI

4 LO
5 LO

4 HI
5 HI

It had a red button on the shifter that was snapped up and down.
I saw it on several tractors that were powered by the famous 6-71.

EXPERTS??

 

[RodeoJoe]

Rob, that's the shift sequence for a 5 speed trans and a 2 speed axle.  The red button on the shift lever operated an electric solenoid on the rear axle that shifted ratios and that's what you heard grinding.  There are still lots of 'em around, they are fairly common in single axle P & D's and used to be used in OLD highway tractors.  One of my dispatchers from years gone by cut his trucking teeth on a Ford flathead V8 gaspot hauling canned veggies across the Cascades with one of those trans setups.  Said it was a bear in the winter for freezing up and they had to get a rag dipped in gas and set alight to thaw the bugger out.

[doug mckenzie]

Spicer offered an air-shifted 4-speed auxiliary on the married-box 4 x 4, or 16-speed as they called it.

[TyYota]

Thanks for your quick responces, how'd you feel about clearing up the rest of my questions:
With a 5&3 or 5&4, wouldn't some of the ratios become redundant (4 hi, and 5 lo are too close or overlaping even)?
Is a truck with a two speed rear axle refered to as a 5&2?
When did air shifted aux boxes become common?
Why would you choose a 5&2 over a 10 speed anyways?
Apperently I'm not the only one here who finds the split shift trannys interesting.
Tyler

[RodeoJoe]

Tyler, with a 5&4 or 4&4 you wouldn't use all of them because as you say some of them overlap.  Usual shift sequence was 1&2, 2&2, 2&3, 2&4, 3&2, 3&3, 3&4, 4&2, 4&3, 4&4, 5&2, 5&3, 5&4.  Only the A box gears weren't labelled 1, 2, 3, 4, they were labelled 60 or 90 under, under, direct, and over.
I've always heard a 5&2 referred to as a 5 speed with a 2 speed axle.

Air shifted auxiliaries were coming in around the late 60's early 70's.

A 10 speed Eaton or Fuller was rated for higher horsepower.  A 5 speed and 2 speed axle was spec'd with gas engines and smaller diesel engines and wouldn't take the torque of the bigger engines.

[W. Lineman]

TyYota the fiirst air shifted splitter I became aware of was the 50's Mack Unishift. That was forgettable.
By the seventies they had a pretty good one, the Mack TRDL107. That one had reverse on the air button, R-N-D-L. So it was simply1L-1D-2L-2D-3L-3D-4L-4D-5L-5D going forward or 1-2-3-4-5 going backwards and you could back it at a real crawl or at 30mph. It was great for backing down farm lanes or blocked haul roads. Going forwards was great too because the button shift took care of most shifts on the road.

I have never seen hydraulics used but I have seen electric buttond for the 2-speed axles Rob Archer talked about. Which I have never heard referred to as a 5&2, I guess because the 2 is an axle not a transmission. There was a three speed tandem axle by the way but that was accomplished by first shifting the front drive axle and then the second. When you have one axle in low and the other in high it acts like a gear in the middle.

From that Model T truck example, there must about always have been auxiliaries. Then some makers like mack integrated them with the mainbox into one and that was like the Duplex Triplex or Quadroplex.

On some I have seen, 5x2, 5x3, or 5x4, there was no duplicate gears, least not on the split gears which was U-D-O on a Quadroplex. The C gear was a crawler for real low hole and 5C made no sense, for example. But there was a lot of em 4U-4D-4O, 5U-5D-5O. But to your point some did have duplications especially if the 5-speed was direct and the splitter had overdrive. Then it made sense to use 4U-4D-5D-5O because 5U was the same as 4D and 5D was the same as 4O. That made it 13 usable shiftable from 1U to 5O, plus the crawler gears which there was overlap there too.

The 4L-5L-4H-5H sequence Rob asks about is called a 'short 4th' and comes when 4th is deliberately real close to 5th. It makes a lot of gearshifting. But on a 6-71 or a 3208 farm truck, it gave you real close steps like a 13-speed does and would run a lot faster on grades if you keep the revs up..

The first good one-stick tenspeed was the Road Ranger and Fuller did that in the earty sixties.  I believe it was the R96. That made everybody scramble for improvement. Then they invented twin countershafts and there was the RT-910. After they invented range shifts (going back throu the big 5 a second time) everyong in the world followed them.  That pretty much doomed the two sticks after a while.

The worst splitterbox ever was the Spicer SST-10 that had the splitter gears ahead of the main and not behind. It would grind, grind, grind no matter how much practice you had.

More recently there has been the Fuller "Super 10" and this is a actually a range box that behaves like a splitter. So the shifting is 1D-1O-2D-2O-3D-3O-4D-4O-5D-5O but inside it's a three speed main with a range in the back and the first two gears in the frontbox used as a splitter. You can hear the range air shift automatically when you move the stick between the 2-3 rail and the 4-5 rail.  Fuller likes this one more than I do. You have to be real patient and wait on it. Then there's a 'Top Two' version of this that automatically shiifts back and forth between the last two but I have driven this and it's even worse because it shifts whan you don't want it to sometimes. (or doesn't when you do)

Bill.

[TyYota]

Wow great replys guys. I think I got a pretty good handle on this whole "brownie" thing now. I'd sure love to jump behind the wheel of a 18 wheeler and slam through 18 or so gears   . We'll see, check out my other post "Getting started in the industry" for my questions about starting driving.
Tyler

[doug mckenzie]

Bill, here's the deal on the Super10.

After 9 years with one, I like it.
You're correct inmentioning that you have to be patient with it. It's a much slower shifting box because with certain engines, and in my own case the 12.7 Detroit, it works best when shifted between 1350 and 1500 rpm. I've road tested alot of guys new to the transmission over those past 9 years, both experienced and "newbies" and they do have a hard time getting used to it's slowness.

What I do like is it's non-repetitive. You don't have to go back through the box, just move the stick upwards and up-shift exactly like a 13 or 18'sDirect to Overdrive 'splits." You can usually start quite easily in 3rd but above 80,000 lbs, you'll get a bit of clutch shudder. I've grossed 105,000 lbs many times over those years but do not recomment starting any higher than 2nd. I always start in 1st, even when empty.

It's a Low Enertia box, so clutchless shifting is very, very easy so long as you don't wind the engine up. With my Detroit, as I've said, never exceeding 1500 makes for a real nice shift and if you're paying close attention, it's quite easy on fuel.

What I have no use for is the Super 10Top2 which I've had for 4 years now.
I consider it junk.

For those who do not know about a Top2 transmission, this is an option on 13 and 18 speed boxes but became standard on the Super10 about 1999 when my current Freightliner was built.

How it works is such: You work up through the transmission in the regular manner and upon reaching 9th, you switch the cruise control on and flip the transmission switch forward. At the appropriate time the engine ECM will interact with the transmission ECM and make the up-shift into 10th.
It's supposed to work smoothly - but I've never seen it happen.

Where I don't like it is simply by leaving the cruise control off until I'm ready to cruise on the boulevard, I can make the appropriate up-shift at what I consider the "sweet spot". Since I'm now paying for the fuel this truck uses, I don't consider a transmission that up-shifted automatically at 1700 or 1800 an aide to my business. Even at 110,000 lbs gross I've run up to 1500 rpm in 9th, made the split and she's still picked up and not cost me any money.

Downshifts are sudden and brutal.
If you can control the engine's operation, do it. I'm not pleased when pulling a hill with the cruise on and see the engine down-shift at 1250 and pick up 9th at 1700 rpm. That costs me money.

With the 3.90 rear I've got, if I wait until the rpm drops to 1150 I can downshift myself and it will pick up 9th at 1500 rpm or a bit less. Less strain on the driveline, less strain on my revenue.
Now remember, these comments are in regards to a Detroit Series 60, so I'm not sure how it would work with a Cummins or a Cat. The Detroit works best between 1300 and 1500 and for fuel economy, which my tractor is spec'd for, about 1450 gives me the best - only I don't have much room to play with because the ECM limits me to 1550 rpm in 10th.

Now, adding more confusion is that not all Super 10Top2's work that way.
In our company day cabs, which use 350-hp 1550 ft/lbs torque Series 60, the company tailored the ECM in such a way that the transmission shifts between 9th and 10th on it's own.

Don't like that.

The Super10 has been replaced by a monster they now call "The Lightening".
It's basically the same as the Super10 only it shifts electronically.

Tried one earlier this week. Went for a little stroll in a new Columbia the outfit I work for has - C12 "Kitten" and this transmission. Not impressed.

[mike b]

TyYota

I use to work for a company that had alot of early 1980s 359 pete log trucks that had four speed auxiliary transmissions behind five speed mains.. I and many others thought this combination was a pain in the #@* because

- The auxiliary transmissions ran very hot in the summer..
- The auxiliary transmissions had a bad habit of blowing tru-shaft seals.. This was a critical problem due to the limited oil capacity of these transmissions..
- The brackets that were used to support the auxiliary transmissions had a bad habit of cracking over time..
- This 5x4 combination made for more potential driveline problems due to the fact they had two extra U-joints when compared to a single transmission truck..
- The shifter forks had a bad habit of getting JAMMED where they met the shift cables if you did not shift them "square"..

_________
mike b

[TyYota]

I've been thinking about this or a while, with a paddle type shift switch on the shifter (like a roadranger) and more than two positions wouldn't it be easy to select the wrong gear? I'm trying to visualise the shifter on an air shifted compund transmission.
Do you have to double clutch to get the aux box to mesh?
On a 4&4 5&4 or 6&4, low gear in the auxillary is used only for starting, correct?
When did the two sticks disapear? in the 60's/70's when air shift came in?
When sifting two sticks did you use two hands and let go of the wheel or one hand and hold on to the wheel?
Tyler