Lockout hubs

[gringeltaube]

The sprague works by sensing the rear axles turning faster than the front. Once it gets to about 7% a clutch engauges and starts sending power to the front. With lock outs on the front, it will always try to put power to the front. So if you put lock outs on a sprague truck, it wears out the disks. Then you will have NO front wheel drive.

You mean the sprags wearing out faster? I would say they last longer, at least the front one, since there wouldn't be any slippage at all when the front wheels are "freewheeling". The sprag just stays engaged sending "power" to the front like you said, making the output and propeller shaft turn at 3049rpm while the rear spins at 3291rpm (2600/5th od. gear). And since normally both front hubs are disconnected it could even make one axle shaft alone turning up to 900rpm (!) if for some reason the other one offers great enough resistance.

I concur with you and others, though: front lock out hubs on a sprag equipped truck just don't make sense at all; either convert to air shift and add two FW-hubs or start with just one hub/axle shaft kit for the center axle.
That is the best way to prevent rear (and front!) tire wear, less money invested and well worth it, IMHO.

G.

 

[russ81]

I don't mean to be argumentative, but this is just not true. No modern 4WD vehicles (at least that I'm aware) of have different gear ratios front/rear. Sometimes it's not possible to match gear ratios exactly if you're putting two different types of axles under a vehicle, and a few % difference is acceptable, especially if its an off-road truck. I don't think any of the Pro 4 CORR trucks even run different gear ratios front/rear, although I'm not sure about that. I have several Toyota trucks that I run in 4WD full-time for thousands of miles without any problems. Some vehicles aren't tolerate that, but it's not because of the gear ratios.

Your not being argumentative, your just misinformed.

Take the 4.11 gear ratio that every one seems to love in their older 4x4's. You will find that a "set" for the front and rear willl be 4.10 & 4.11. It's not a large difference, but it is there.

 

[KaiserM109]

One other thing that has not been mentioned.

Today's modern 4x4's use a different gear set for the front and rear differential. The front axle uses a faster (numerically smaller) gear set to "pull." This aids in steering. If you had a faster gear in the back you would be "pushing" the front end causing your steering to wonder more. This does have a significant draw back. Going on pavement causes your drive line to "load up" making your tires chirp relieving the built up pressure. That is why it is recomended to only use four wheel drive on surfaces that allow slipping, and to not stay engauged at high speeds.
Case in point. A guy I work with's wife drove his truck from Ohio to Arizona in four wheel high running an average of 80 mph. So far he has completely rebuilt the entire front axle (most of the parts were BLUE....this means the parts were at least 400 degrees), last week he had to have the transmission and transfer case both rebuilt, and he had to have all new seals installed in the rear axle.

Unless you are driving in a straight line, and at low speeds, you HAVE to allow at least 3 of the tires to spin at a different rate at different times or else you are wearing parts. That is why when you get a 2 wheel drive truck or a car stuck in the mud you only get 1 wheel drive. And, it is never the wheel you need to spin. Remember, PATH OF LEAST RESISTANCE. What ever is free to spin, will.

I disagree strongly. If you were going to mismatch ratios for the purpose of improving steering in a turn, you would put the higher (lower numbers) ratio up front because it tracks the larger circle.

What has happened in the past is Ford manufactured its own rear axles and bought their front axles from Dana. In many cases Dana and Ford didn’t have exactly the same ratios to offer. It is considered “close enough” if the ratios are within 0.07. My dad bought new a ’70 F100 that was passed to me and now to my son. It has a Ford 9” rear axle with 3.50 ratio and a Dana 44 in front with 3.54 ratio. That mismatch almost put me over a cliff on Mclure Pass in 1970 when I engaged the front on a downhill run on a slick road. I completely lost steering because the 2 ends were arguing about how fast to go; the front lost.

Sometime in the late ‘70s Dana started manufacturing a 3.50 in a Dana 44 for the 2nd generation Broncos. I am in the process of putting one in my Original Bronco instead of the 4.11 ratios. I am also putting an NP435 with a ‘granny gear’ to get the low end back.

I have never seen a Jeep or a GMC vehicle that mismatched axles. I have seen Dodges that did exactly the same thing as Ford. I have also seen Dodges with limited slip axles and a 3rd differential in the transfer case to allow different axle speeds.

When my deuce bubbles up on the $$ priority list, I will start fixing it up. After new rubber in wheel cylinders, shaft seals and PS, a rear lockout hub will be next; then front hubs.

 

[oifvet]

Putting a single lockout on one of your rear hubs will keep the 2 axles from fighting to go in a straight line. To make a turn without a hub, one of the 4 pairs of duels has to slip.

A single hub in the back has 2 BIG advantages:
1) The original military NDT (we used to call them "tactical") tires are dangerous at best on slick roads, i.e. ice and rain. A lockout on a rear hub will make the whole thing follow in a turn better. The front tires don't have to fight the back ones so much.

2) It will make non-power steering at slow speed a little easier.

I've seen on this website where guys (gals too) will pull a rear axle and replace it with something (maybe a broken axle) to keep the end sealed. That will do the same thing.

Hence the reason for my Ouverson on the forward-rear dual.

Not for fuel economy.

The deuce and fuel economy don't get along.

 

[jesusgatos]

Your not being argumentative, your just misinformed.

Take the 4.11 gear ratio that every one seems to love in their older 4x4's. You will find that a "set" for the front and rear willl be 4.10 & 4.11. It's not a large difference, but it is there.

Well, one of us is wrong and I'm pretty sure it's not me...

 

[KaiserM109]

Your not being argumentative, your just misinformed.

Take the 4.11 gear ratio that every one seems to love in their older 4x4's. You will find that a "set" for the front and rear willl be 4.10 & 4.11. It's not a large difference, but it is there.

Well, one of us is wrong and I'm pretty sure it's not me...

Okay, I was going to shut up, but 1 more story.

In ’70 I got out of the Army and went to work for my dad for a year and he agreed to pay my tuition at CU. We had a TV translator installation in SW Colorado and we borrowed a well used Ford F250 (former Forestry Service Truck) that had 1/8 turn of backlash in the rear axle (bad!). We would load it up with 1/2 yard of wet concrete and run up the mountain to drop it into holes for 100’ towers. We locked the hubs in and put it in 4x4 as soon as we got off the main road. The road was dry but in real bad shape.

Every 100 yds, or so when I hit a big bump it sounded like someone hit the drive shaft with a hammer, HARD! “CLANG”. We couldn’t stop until we got the concrete out of the truck. Five miles every 100 yd. “CLANG”.

We went back to the owner and he said that he had had the same experience and that they had even opened up the differential to see if it was jumping teeth.

After dropping our load following the second trip Dad said “I know what the problem is. Crawl under there, Son, and tell me what the ratio tags say. As he expected they were different. What was happening was the system was “loading” up and finally got to the point where there was a lot of force. With 1/8 turn of slop in the rear diff (who knows how much in front) it took 100 yards to reach critical mass. On the next big bump a wheel would spin backwards, relieving the stress and it would go “CLANG” when it got to the end.

I come from the mountains of Western Colorado. I learned to drive in a ’48 CJ-2. The Western Slope, as we call our piece of Paradise, if 4x4 Ford country. I have owned many and worked on many more and scrapped out a few. The 3.50 Dana I am putting in my ’69 Bronco was just sitting out at the junkyard and I couldn’t find out what it came out of, except its track and spring mounts were the same as a 77-79 Bronco. When I get it installed in front of my Ford 9” with 3.50 ratio (extremely common for Ford light trucks), it will be the first matched Ford I have ever seen.

Ford Broncos from ’65 to ’76 usually had 4.10 in the rear and 4.11 in front. F100s had 3.50 in the rear and 3.54 in front.

 

[wheelspin]

I disagree strongly. If you were going to mismatch ratios for the purpose of improving steering in a turn, you would put the higher (lower numbers) ratio up front because it tracks the larger circle.

What has happened in the past is Ford manufactured its own rear axles and bought their front axles from Dana. In many cases Dana and Ford didn’t have exactly the same ratios to offer. It is considered “close enough” if the ratios are within 0.07. My dad bought new a ’70 F100 that was passed to me and now to my son. It has a Ford 9” rear axle with 3.50 ratio and a Dana 44 in front with 3.54 ratio. That mismatch almost put me over a cliff on Mclure Pass in 1970 when I engaged the front on a downhill run on a slick road. I completely lost steering because the 2 ends were arguing about how fast to go; the front lost.

Sometime in the late ‘70s Dana started manufacturing a 3.50 in a Dana 44 for the 2nd generation Broncos. I am in the process of putting one in my Original Bronco instead of the 4.11 ratios. I am also putting an NP435 with a ‘granny gear’ to get the low end back.

I have never seen a Jeep or a GMC vehicle that mismatched axles. I have seen Dodges that did exactly the same thing as Ford. I have also seen Dodges with limited slip axles and a 3rd differential in the transfer case to allow different axle speeds.

When my deuce bubbles up on the $$ priority list, I will start fixing it up. After new rubber in wheel cylinders, shaft seals and PS, a rear lockout hub will be next; then front hubs.

my 1995 wrangler had 411s up front and 410s rear, dana 35 rear vs 30 front factory.
?????? i don't know, but it works.

 

[tm america]

alot of the mud drag trucks overdrive the front tires to be able to steer better .but for the street or on a heavy vehicle its unfeasable to do since things wont hold up on a hard surface . also a sprag transfer case is just that it lets things free wheel one way and hold the other way .no magic number on slippage allowed as soon as the back tires are going faster than the front the sprag looks and when the fronts go faster then the rears it unlocks.this is why trucks with a sprag transfer case have a rod going from the t.c to the trans to lock the transfer case in when in rev or you would have no front axle engagement in rev.they're not set up like a gov lock it's just a sprag when things are going the same speed it is locked but not loaded .the reason the lockouts dont help on a sprag t.c is thing are being turned be the transfer case not the wheels.just my two cents

 

[wheelspin]

so in theory, could you take the rod off from the trans and hook it to a shifter in the cab? this could allow a in and out operation of the front? has any one tried?

 

[gringeltaube]

Read here.....: https://www.steelsoldiers.com/threads/sprag-conversion.31794/

G.

 

[chaplain]

I read through the whole thread and I am sold on the idea of locking hubs. I have had them for years and I am even more sold on them for the deuce. Two questions come to mind.

1.) I am pretty sure that I have air assist on my truck. I am still learning many of the parts and nomenclature on my truck. I have a switch for the front axle that hisses when engaged and disengaged. Hmmm, sounds like air assist to me. So how is a sprague system identified?

2.) With all of the talk about the rear axles I was wondering which of the two axles gets the most wear. For example, If I were (I'm not going too) to bob my truck which would be the better axle, the front rear or the rear rear?

 

[stumps]

Your not being argumentative, your just misinformed.

Take the 4.11 gear ratio that every one seems to love in their older 4x4's. You will find that a "set" for the front and rear willl be 4.10 & 4.11. It's not a large difference, but it is there.

Sad to say, but in '86, at least, Ford doesn't agree with you at all! All of their 4WD trucks use the same ratio front and rear. I verified this by going through my service manuals, and by checking the tags on my truck. My F250 has a Ford 10.25" limited slip in the rear with a 4.10 ratio, and a Dana 44HD in the front with a 4.10.

This requirement is so obvious that Ford doesn't even bother putting the front axle's ratio on the truck's VIN/line tag. They only tell whether the front axle is, or isn't limited slip. The ratios are on both differential's tags, however, and they are identical.

If you were making a truck that was to run off road in mud or snow all the time, it might be beneficial to have the front driving a little faster than the rear, but on a paved road, where you might go from snow to hard pavement, it would be suicide.

Even with equal ratios, and equal diameter tires, the front tires go farther in a turn than the rear. That will bind up a transfer case that doesn't have a built in differential, and your wheels will hop, and u-joints will break.

Because of the accelerated wear of front tires, the front and rear tire diameters are usually slightly different. This will also result in wheel scuffing and hopping even in dead straight travel on hard pavement.

AWD vehicles, like the Subaru's have a limited slip differential built into the transfer case to handle these differences.

What you claim just doesn't make sense. Show us some documentation.

-Chuck

 

[Ferroequinologist]

I read through the whole thread and I am sold on the idea of locking hubs. I have had them for years and I am even more sold on them for the deuce. Two questions come to mind.

1.) I am pretty sure that I have air assist on my truck. I am still learning many of the parts and nomenclature on my truck. I have a switch for the front axle that hisses when engaged and disengaged. Hmmm, sounds like air assist to me. So how is a sprague system identified?

2.) With all of the talk about the rear axles I was wondering which of the two axles gets the most wear. For example, If I were (I'm not going too) to bob my truck which would be the better axle, the front rear or the rear rear?

Spraque trucks have no air valve on the dash.

The wear on the rear axles isn't the biggest issue when deciding which axle to put a lockout hub on. If you were going to bob it, you could leave either axle, but if you left the rear it would still be as long as a stock deuce, so I'm not sure that would count as 'bobbed'.

If you take the drive shaft out from between the rear axles, then you are only driving the 'middle' axle. This creates alot of 'wheel hopping' on the middle wheelset. It is pretty universal to put the lockout on the driver side of the middle axle and then the truck is driven only from the rear most axle. Helps with the hop.

 

[jatonka]

Skipping around a little, as far as pickups and gear ratios go, in 1972 when I was planning to buy my first new truck, I visited Ford and GMC dealers around North Jersey. They all told me don't run 55 mph in 4 wd because the ratio in the front axle is 4.10 and the rear axle ratio is 4.11. They explained that would cause a torque build up at high speed on hardtop roads. Front axles always pulled a bit more than the rears pushed in those days on civy vehicles.
Now, on to lockout hubs, Hubs for the front axle help reduce axle parts wear and reduce inertia which tends to make the truck go straight when you want to turn. also reduces drive shaft u-joint wear on front driveshaft. seems to help fuel economy some and might reduce front tire wear a little too. Also gives you two front drive flanges to put on the forward rear to replace the 2 axle shafts, thus disengaging the forward rear, leaving the rear rear to do the driving. Worked out well for me on a cross country 7000 mile trip in summer of '08. JT out

 

[spicergear]

JATonka- I think it was back in 2000 give or take a year or two and I was in a Dodge garage and they had a new dually up on the rack. I walked under the truck to look at the rear and they were tagged 4:10 & 4:11's. I pointed it out to the service manager, an acquaintance of mine and he had never heard of it before. Really? -

Chaplain- As far as the which rear question for a hypothetically bobbed truck...it won't matter. In stock form they both push, jump on occasion, and scrub. They're also virtually never going to get worn out in a low power truck rated at 10,000 load. I put a rear from a '53 gasser REO in the rear of my big M715, Velvet, and it wasn't even leaking when tore it down to put on the high clearance pan and Detroit Locker. The new seals I added leak though-

 

[JTugwell]

INMO i would think that a major benefit of having locking hubs would be in case you ever had a catastrophic failure of the front axle. If you were trail riding one day, and broke a shaft, rounded off a ring gear, or blew an oil seal you could simply unlock the front end, and drive it home with nothing more than the drums spinning on the hubs. i guess in theory you could just remove the stock hubs, but itd be nice to keep mud and crap out of the places where you dont want that stuff.

 

[spicergear]

The guys with 46" tires (aka TRACTION) on the front axle should read the above thread since the No Darn Traction stockers will slip on wet leaves. Oh, or tractor pull hopping on blacktop may do it too-

 

[Csm Davis]

look guys , if you put your truck up on a lift with the t.c. in rear wheel drive, and run it at hwy speeds everything turns at the same speed very shortly, this is why I don't bother with lockouts. The main trucks that need lockouts are the one's with locking diff's in the front or midddle axel to prevent binding, and long haulers for mileage and some wear. I only make short runs in my m35 and want to stay dry when I need 6x6.
As to most 4x4 ratios there were some that had 4.10 and 4.11 mismatch but it is not considered proper, if you can match exactly you are better off in the long run. Now the thing is most civi trucks have open or limited slip diff's that even on pavement will releave most of the binding. I have built trucks for mud bogging that had diffrent ratios front and rear but even some of them question if it works.

I worked in a driveline shop and I have a A.S. in heavy equipment repair.

 

[Unforgiven]

Hence the reason for my Ouverson on the forward-rear dual.

Not for fuel economy.

The deuce and fuel economy don't get along.

Do you have any pics/pages explaining this conversion? How do you convert one of the rear axles to have lockouts? Are there any pre-made, bolt on kits available for this?

 

[dabtl]

All you need is a lockout and a dual splined axle and the gaskets.