I was reading in the newest Diesel Power magazine about how they installed locking differentials in order to obtain better fuel mileage. On paper it makes since, so would it would for a CRD or gasser Liberty of the 2002-2007 years?

I'm a long time lurker and first time poster. I hope when I get my welding and fabrication degree I can buy a 2005/2006 CRD so I can live out my dreams of driving diesel power. Ideally I would want it to be more fuel efficient and cleaner than how it was made from the factory. I will formulate more questions over the coming weeks. Thanks to anyone advance who posts comments on the subject.

Bye for now!

Erik

from what I understand, carrying out the whole ordeal for the libbys for locking hubs would cost enough to where you'd probably never get your investment back

There's a thread around here somewhere that someone had discussed that route

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03 Renegade (Black)
177k miles 3.7L gas - 45RFE
Command Trac / 4.10s
Lift: ft. 790+ rr. JBA4+
The last of the TrailReady Front&Rear Bumpers and TR Rock Rails
Jarhead Offroad light covers
31x10.5R15 RedLetter Grabbers on Blackrock Dunes
L.O.S.T #KD098632

There is no question that having front hubs (open) relieves the engine of the stress of always turning the front end. It cant not equal better mileage! I asked about this when I first got on the site and nobody knew of any front hub kits in existence for the KJ. So, I guess short of a front axle conversion youre not going to find front hubs available for the KJ.

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2006 KJ CRD Ltd - Suncoast, GDE Eco, EGR Delete, After market T-Stat, Skid Row skids, V6 airbox, 2.5" Turbo back
2005 KJ CRD Sport-Suncoast, Transco, GDE Hot-GDE Trans, EGR Delete, Skid Row skids, V6 airbox, 2.5" Turbo back, After market S-Stat
1987 Suzuki LWB Samurai -diesel powered, custom 4 link coil suspension 38.5 SX Swampers

Welcome to the forum. Nice to see another Elgin resident, especially one interested in biofuels. After Eugene is paid off, I will start looking for diesel motor to stuff into into one of my vans and run veggie. Right now I'm thinking the MB 3.0L in the current Sprinters would be a good fit.

Back on topic:
Was the vehicle that DP installed the hubs on SFA or IFS? Are you familiar with the working of locking hubs? H&H or Midwest Automotive on Bluff City has an old Blue CJ with some nice looking locking hubs in their yard. You might be able to get them cheap enough to modify into Liberty hubs. I'd help you pull them, but I'll be at the LOST Jeep Safari/Moab run till July 23 and they might be gone by then.

I could see it saving some fuel, since the shafts and diff would no longer be adding resistance. If it would be enough to offset product costs would depend on distance driven. Did DP state a specific MPG increase? The hubs could also be beneficial to someone if they break the D30a.

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Aaron

A vehicle isn't yours till you learn to wrench on it yourself.

2002 Jeep Liberty Sport (Eugene, I am the Passenger, And I ride and I ride.)
1999 Chev Astro 2WD (Green, Daily Driver)
1997 Chev Astro AWD (Grumpy "The Heep", $250 Rally Van, 335k miles, 2" lift, 31" tires)

Hey,

There are a few Elgin guys on here believe it or not. I've seen one guy around the area break the tires and throw black smoke everywhere. I saw him head south on Randall rd. It was black and it sound nice.

If you really wanted to swap an engine in one of those vans, just got with a Cummings 4BT. Sprinter motors are pricey and more expensive to maintain.

Back to the subject:

I would rather just put on locking hubs made for these rides and are new. Diesel Power magazine said that they gained a 1.1 mileage increase. Realistically though that was on a bigger ram that is overall much heavier than one of these things. Personally I'm sure with aerodynamic, engine, and drive train mods you can get a reliable 30MPG out of these things. I'm sure some are already doing it now.


Erik

Thank you to everyone that helped me out by posting any info you have on the subject. I appreciate the responses and ultimately cost over benefit will determine if its ultimately worth it or not. Realistically I want to build a CRD that is getting at an average of 30MPG and can last me for many highway and towing miles to come. In a nutshell, I'm going to need the help of CNG injection, water injection proper tuning, free flowing inlets and outlets, make it more aerodynamic (can you say air tabs and moon eyes?!), while making the drive train mechanically efficient, and more importantly, reliable.

Would it be worth it do both the front and rear with locking hubs? Truthfully what is the real advantage of this and why do so many do it? Rock crawling? Towing? I looking at this from a MPG standpoint.

Erik

Oh, I'm aware of the others from Elgin. The last LOST Illinois gathering/wrenchfest was at yellocoyote's and my house. Just nice to see yet another added to our ranks.

Black, breaking tires, and throwing black smoke....that sounds like Andy.

I have looked into the 4BT since it will take most of the same mods as the 6BT. However it's a little tall for the van's engine compartment. Minimum 2" sub-frame lift needed, which is OK since I plan on lifting the receiving van anyway. I just like that the MB is a more modern/cleaner engine, the V6 layout helps too. I really should find the dimension of one to see if it fits without mods.

BOT:
Unfortunately nobody make locking hubs for the Libby yet. Looking at the posts on this forum the market isn't there for one of the big name companies to tackle it. You could be the first if your fab skills are good enough and a set of used hubs would be a good jumping off point cause they would show you how they work and you could use some of the parts to reduces the number of parts that need to be created from scratch.

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Aaron

A vehicle isn't yours till you learn to wrench on it yourself.

2002 Jeep Liberty Sport (Eugene, I am the Passenger, And I ride and I ride.)
1999 Chev Astro 2WD (Green, Daily Driver)
1997 Chev Astro AWD (Grumpy "The Heep", $250 Rally Van, 335k miles, 2" lift, 31" tires)

I think you are confusing locking hubs with locking differentials.

Locking hubs allow the wheels to spin separately from the drive train. Lets the vehicle roll like it's a 2WD and get better gas mileage. I've never seen locks for rear hubs.

Locking differentials force both wheels on an axle to turn at the same speed. This helps in off road situations when the main drive wheel doesn't have optimal traction. Not recommended for on road use.

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Aaron

A vehicle isn't yours till you learn to wrench on it yourself.

2002 Jeep Liberty Sport (Eugene, I am the Passenger, And I ride and I ride.)
1999 Chev Astro 2WD (Green, Daily Driver)
1997 Chev Astro AWD (Grumpy "The Heep", $250 Rally Van, 335k miles, 2" lift, 31" tires)

Great overview of locking hubs with diagrams.
http://www.4x4abc.com/4WD101/hubs.html

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Aaron

A vehicle isn't yours till you learn to wrench on it yourself.

2002 Jeep Liberty Sport (Eugene, I am the Passenger, And I ride and I ride.)
1999 Chev Astro 2WD (Green, Daily Driver)
1997 Chev Astro AWD (Grumpy "The Heep", $250 Rally Van, 335k miles, 2" lift, 31" tires)

Better break out the credit card if you thinking of trying to make lockout work on a KJ......................

You will need.................

Custom CV shafts make with longer outer stub axles.
Custom knuckles.
Custom spindles made
Bearings,seals

Everything will need to be custom machined/made.After the one-off custom costs you could have done a SFA swap.I will be using lockouts on my SFA swap for the time being but I will be wheeling my KJ and they will break(they always do),I want to see what are the limits of them then I'm installing the set of drive flanges I already have that will make my lockouts permanently locked just like how the KJ was from the factory.I have been running around in my KJ for 1 year with no front drivetrain(no diff,no CV's,no driveshaft) and did not see any mpg increase.

well if you got diddlydooda up front than theres going to be nothing noticeable for non sfa's to gain through the lockouts in terms of mpgs

ya typically bounce them between 12 and 20 mpg and that's about as good as it gets until you shed weight atleast with the gassers

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03 Renegade (Black)
177k miles 3.7L gas - 45RFE
Command Trac / 4.10s
Lift: ft. 790+ rr. JBA4+
The last of the TrailReady Front&Rear Bumpers and TR Rock Rails
Jarhead Offroad light covers
31x10.5R15 RedLetter Grabbers on Blackrock Dunes
L.O.S.T #KD098632

Gearing correctly for tire size(if lifted) is what get your mpg's back .I'm going to 35" tires and adding about 500-1000lbs of weight and I'm expecting a mpg increase from gearing correctly now.

The best I saw with stock sized tires is 23mpg's,the best I saw lifted and at 5500lbs(1500lbs over stock) was almost 22mpg's(21.9mpg) on the highway,not bad for a brick.

Hold on what do I need to do to get 22mpg lol i get around 17 on standard and i drive 60/50 hwy/city
what gears where you running at the time?

With stock sized tires I had the stock 3.73 gearing and no added weight(pretty stock KJ).I was running 265/75's and 1500lbs extra weight on my KJ and could always get very close to 22mpg's on the highway at 70-75mph with 4.10 gears,it would have been much better mpg's if I could have went to 4.56 gears.Now city driving I'm still guzzling gas at a tune of 10-13mpg's(winter/summer) since I live in Colorado and your always starting uphill from a stop all the dang time .With the gear ratio I'm going to with my SFA swap(5.13 gear with 35" tires) I'm actually expecting at least 20mpg's+ for city driving and at least 25+ on the highway if I don't run much past 70mph.

before i started stripping this and that and adding this and that i put about 12000 purely highway miles on my kj (stock with a really sagged suspension lol) and it stayed between 20-22 with 3.73 and 235-70's

since I lifted it - added a roof cross rail and another 40 lb skid it's since gone down to about 18 on the highway

it will eventually get regeared to 4.10's whether or not i go up to 30.5+ in tire size or not

hopefully i'll get a chance to regear soon as i move and don't have to do 700 mile round trips so often - i simply don't have time to do it at the moment

atleast in my opinion (not that it matters much..)

but i kinda feel that it should have came with 4.10's to begin with BUT.. you can say that same sort of statement about several things but that's just how it is!

_________________
03 Renegade (Black)
177k miles 3.7L gas - 45RFE
Command Trac / 4.10s
Lift: ft. 790+ rr. JBA4+
The last of the TrailReady Front&Rear Bumpers and TR Rock Rails
Jarhead Offroad light covers
31x10.5R15 RedLetter Grabbers on Blackrock Dunes
L.O.S.T #KD098632

Your mileage will suffer greatly if you unlock all 4 hubs

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2007 KJ Sport - Frankenlift

They used to put lockout hubs on smaller 4x4s....but if you noticed, Jeep hasn't done it since the 80s!! Everything new has full-time hubs.

I've done some research on this and basically it comes down to on a small 4x4, the mileage gained by having lockout hubs (and not having to have the motor turning the axle shafts as a result of forward motion spinning the front tires also when in 2 wheel) was negligible for smaller 4x4 vehicles. Plus, there are way more parts to deal with when you have lockouts, and they can assemble the vehicle more quickly if they don't have to assemble all of the lockouts!!!

For big trucks, I believe like 3/4 to 1 ton and up, the mileage increase becomes noticeable....like approaching 1mpg or so, sometimes more. So on heavy duty stuff, they still use lockouts. But for a 1/4 ton jeep (wrangler/cherokee/liberty/grand cherokee, etc) the mileage increase is such a small fraction of a mile per gallon, it really isn't worth it.

Now a days most people who swap in D44s and D60s up front ditch the lockouts and use slugs, which....is basically what you have on your liberty, only they have the serviceable wheel bearings and such.

I wouldn't bother swapping lockouts onto the front of a liberty, unless you were putting a D44 in there that had lockouts!!

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Civilisation exists by geological consent, subject to change without notice. -Durant