# Using a 2-speed rear axle



## Kaptain_K

Sorry for this stupid question but I've never used a 2-speed axle before.
Do I need to use low/high sequence all the way up and down the gearing?

It confuses my brain to follow the instructions mounted on the dash:"When going from low to high, shift axle first, then trans....and when going from high to low, shift trans first, then axle(or maybe it's opposite, like i said it confuses me). Instead I've just been using HIGH 2-3-4-5 when empty and on the Interstate, and LOW 1-2-3-4-5 when loaded...and then I'll put it into HIGH-5 if on the Interstate. Seems to work fine. Good enough?
thanks!
Kapn K


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## TDunk

When your running empty you shouldn't have to "split" the gears. First and second you probably don't have to worry about splitting unless you have a HEAVY load on. When your about to shift into 3rd (or in the process of shifting, depends on if you have a vacuum operated or electric 2-speed rear) push the splitter button down and continue shifting into 3rd, now your in 3-low. Build your RPMS back up and let off the gas at the same time you pull the splitter button up. Now your in 3 high. You don't need to use the clutch for this part. You'll hear some grinding in the rear end, that's ok. Once you get used to the truck you'll be able to time it better so it doesn't grind as long. Keep re-peating the same process until into fifth. 

To down shift, let off the gas the same time you push the splitter button and rev the engine (no clutch) until you feel it engage. Don't rev it super fast, but not to slow either. You'll hear some grinding during this too. The tricky part is downshifting a gear and trying to split it too. That takes a little practice. The problem alot of people have (climbing a hill) is they lug the engine to far down and don't give themselves enough time to split/down shift and split. Just don't let your rpm's drop to low before you try and split or you'll be stopping in the middle of the hill and starting out from a dead stop.

It takes practice to get good at it, and every truck is a little bit different. Hope this helps some.


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## Rookie1

You need to go out and drive the truck around and see how it acts. I drove a F700 dumptruck with a diesel engine and needed to split most of the gears. I also drove a F600 mechanics truck with 390 gas engine and left the axle in high. As said all trucks are different. Go out and practice somewhere secluded so nobody sees you grinding gears.


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## outdoortype

*Don't use clutch when just going from High to Low*

TDunk made some good points. When I was unloaded, I would just start out in 2nd Low. When the RPMs increased, I would push the clutch in and flip the button to High range and just shift through the gears on high range. If you're going up a hill and your RPMs start to drop: hold the accelerator down, push the button down to low range-don't use clutch. Let off the gas and you'll feel it shift into low range. Push the button and sort of "pop" the gas pedal.
IF you need to "split the gears" say 3rd High range to 4th Low range: Push the clutch in, shift from 3rd to 4th. Just as your letting the clutch out, push the button down to low range. Going from 4th low to 3rd High, Push the clutch in Pull the button up (high range), then shift into 3rd gear. It takes a little while to feel when to push the button in relation to the clutch/RPM when splitting, especially when going from High to Low.


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## B-Edwards

Don't make the mistake of thinking you have to shift gears as fast as you can. I like watching younger or just plain dumber people drive trucks. They try and make sure they hit every possible gear when they don't need to. They try and wind the engine until its about to blow and then speed shift to the next gear. All the while looking like a complete idiot to anyone who understands how to take care of equipment. You have good advise so far, take your time and try to understand it and "you will never have any trouble with a transmission. 



I used to drive an 18 wheeler west coast every week for 3 years. I had an older partner for awhile who was a WW2 vet. I tried my best to be as smooth as possible while driving for 2 reasons,1- he was an older fellow who had experience and i wanted to impress him 2- he was older and I respected him and wanted him to be comfortable while he tried to sleep. I never told him I was trying to accomplish this and I was rewarded when he told the owner of the company that I was the smoothest driver he had ever ridden with. I'm not bragging, I'm just saying try and be serious and you will have no problem in the end.


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## TDunk

I've driven plenty of trucks before with an electric rear, those were great. They shift quicker and have more power so you can get the transmission into the next gear before you have to push/pull the splitter button and by the time you get back into the gas the axle has already engaged. 

The vacuum operated two speeds are pretty much the same but you have to almost "pre-select" your next move. They don't move as fast and don't have as much power to engage. 

All the advice given is top notch, these guys know there stuff.


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## Kaptain_K

Well I do hear occasional grinding, so I must be doing it right! 

Thanks for the help folks. It'll take a little practice but I'll figure it out. 
~Kap't K


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## ropensaddle

Well I only use low for yards hills off road stuff in my f800 if rpms start to lug I downshift on grades but other than that it stays in high. I don't like the grind and occasional ca-chunk and don't want to replace the pumpkin axle or twisted driveshaft that I see with shifting on the fly. I can stay in high and I only use the clutch from a dead stop or downshifting. 



Now get in my r-modle Mack twin stick 5 reverse gears 10 forward two sticks hmmmm
took me a little time to get er right but really I do it the same it has plenty power to stay in high without lugging even loaded and the low is great off road but the 5 reverse kicks arse lol!


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## HorseShoeInFork

I remember my first time driving a two speed. Old worn out POS C70 Chevy dump. Hauled crap for my uncle around job sites. I would shift that thing and use every gear it had. Never got over 25mph. Even though I was screwing off, it did help me learn what did and didn't work. If loaded, probably split them all. Clutch to start in 1st, pull up knob, don't clutch just let off gas pedal, it will shift. Push knob in push clutch in shift to low side 2ND, pull knob don't clutch just let off gas, repeat as necessary to get to high 5. 

There are different types of 5/2's. I have also driven one that split 1-3 high/low, then shift to low 4, then low 5, then high 4, then high 5. I think it is called a 'working 5th' or something.

Best way to learn is to just go do it till you get it right. You will probably be that guy holding up traffic on the interstate, or the guy who has to pull over on the side of the road because he missed a gear and now it won't go into anything except 'grind 1'. Or the guy who is sitting on a real steep hill with the vinyl pinched up because he tried to downshift and missed, and now has to back to the bottom and start over. 

Just remember, if you miss one or grind a lot you are trying to match the engine speed to the gear speed. So if you rev the engine slowly through the RPM range and push or pull on the shifter, it will fall in eventually. Have fun.

☺


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## Crofter

ya, as long as you can stand the noise, you will find one that fits eventually( sometimes like you say after you have ground them all the way to a stop.

I think I have heard that tranny with the irregular splits at the top, called a 
"Short Four"

Ropen, yes you can get some wild grinds and ka bangs and I agree that a lot of the splitting is unnecessary but some of the old 4 and 5 tons from the sixties had only the same engine as a car and if you were overload as they usually were, you had to throw a gear at them at every chance. I pulled float trailer occasionally with a 5 speed and two sp axle on an international 343 on propane. Gutless! Every hill you had your heart in your throat like a chickens gizzard.


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## ropensaddle

Crofter said:


> ya, as long as you can stand the noise, you will find one that fits eventually( sometimes like you say after you have ground them all the way to a stop.
> 
> I think I have heard that tranny with the irregular splits at the top, called a
> "Short Four"
> 
> Ropen, yes you can get some wild grinds and ka bangs and I agree that a lot of the splitting is unnecessary but some of the old 4 and 5 tons from the sixties had only the same engine as a car and if you were overload as they usually were, you had to throw a gear at them at every chance. I pulled float trailer occasionally with a 5 speed and two sp axle on an international 343 on propane. Gutless! Every hill you had your heart in your throat like a chickens gizzard.



I just drove 3 hours in mine today I guess I should have said usually I decided to tow my tow behind grinder and some long drawn out hills had me thumbing in the higher ranges! But on both my trucks 6th or high 1st gear will take off from a dead stop loaded so if I thumb it is only to pull a hill or downshift to slow speed down hill to keep brakes cool.
The main thing is all trucks are different and I drove a real nice sterling crane last year
that thing had me looking like a novice but the owner could hit every gear bam bam bam.
I don't care if you are a terrific truck driver with millions of miles you have to learn you truck!


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## Rookie1

ropensaddle said:


> Now get in my r-modle Mack twin stick 5 reverse gears 10 forward two sticks hmmmm
> took me a little time to get er right but really I do it the same it has plenty power to stay in high without lugging even loaded and the low is great off road but the 5 reverse kicks arse lol!



Oh man Rope I used to drive a Mack with that setup. It was the best dumptruck I drove in the city. Nothing could stop it. Set me up for a few years later when I had to drive a 4x4 Kenworth. 16 forward and 4 reverse. That took some learning there. Too bad that soon truckers will never know what a twinstick is and soon what a clutch is with Allisons getting popular.


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## TDunk

ropensaddle said:


> Now get in my r-modle Mack twin stick 5 reverse gears 10 forward two sticks hmmmm
> took me a little time to get er right but really I do it the same it has plenty power to stay in high without lugging even loaded and the low is great off road but the 5 reverse kicks arse lol!



There are people around here that still drive those, mainly dump trucks. But you can't beat those things.


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## ropensaddle

TDunk said:


> There are people around here that still drive those, mainly dump trucks. But you can't beat those things.



Yup there tough camel back suspension mine is a grapple it is definitely not a beauty but boy howdy it sure is a beast. Every time I get in it I get a tude and start thinking of mad max movies lol. No one wants to play


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## TDunk

ropensaddle said:


> Yup there tough camel back suspension mine is a grapple it is definitely not a beauty but boy howdy it sure is a beast. Every time I get in it I get a tude and start thinking of mad max movies lol. No one wants to play



They definitely don't have a good ride, but other than replacing the elephants feet once and a while and the trunion bushings every once in a great while, they are rock solid. I knew how to turn to old macks up even before i could drive there twin stick. People now a days see a big truck smoke they think is old and worn out, little do they know it just raw power (unless they know trucks)


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## wahlturfcare

Kaptain, i m from the des moines area and can show you how to run it sometime if you need. I have a f 450 with a 2 speed setup and used to have a 2 ton. Just private message me if you need any training.


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## Kaptain_K

Howdy Wahlturfcare,
I've seen your name around for several years....hope biz is good!
I think I've got enough great advice here, I just wasn't sure if I was breaking any cardinal rules on using a 2-speed rear. Sounds like i'm doing just fine, a little grinding can be normal, not split-shifting up and down every time is fine, and most of all, each truck is different, so just get to know it....I can do that! Thanks for the offer! 
~Kaptain


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## Big Jim

B model Macks 4 ever.When you can split em with 1 hand (right arm )on the aux. box and the other (left arm ) thru the steering wheel on the main double clutching em up your a driver.Showing my age here now.
Our old F700 bucket has a electric 2 speed rear.Only time we split it is when were loaded or towing.Just try splittin the higher gears.Bring the rs up in low range ,stump on the clutch while pulling up the button ,listen for the click with a slight a grind and you should be in high range.DONT try and rush the shift or the high range fork in the rear wont have time to engage and you will miss the shift.When down shifting lug it down ,step on the clutch whack the throttle push button down and listen I repeat listen for the click/grind to happen and you should be in low range.Practice makes a driver.SMOOTH is the key to holding a drive train together.
Big Jim


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