can some one explain to me what a live axle is.. what it does.. and how is it better then others.. if it is

 

the way i was taught, read and understand is a live axle always has the axle shafts spinnging with the front wheels. they are not recieving any power input because the transfer case in enguaged in 2wd. once in 4wd the shift fork (or whatever is used now) shifts inside the t-case to enguage both driveshafts.

 

The only advantage is that you don't have to wait on engagement or get out of the truck to engage the hubs, but everything in the front diff and the front driveshaft is always turning, it wears everything quicker than if you had locking hubs and possibly robs some gas mileage having to turn all the front drivetrain over when you are moving.

 

Thats all myths.

That is not the only adavantage. Another big advantage of it is not having the mechanical parts of a locking hub to fail.

Live Axles do NOT rob gas milage. Look at the milage that identical 2wd and 4wd trucks get. Its near identical.

Live Axles also do not wear parts faster, at least not in a sense that will mater in the life time of a vehicle. Under normal conditions a differential (R&P) will last what, forever? You can go to the junk yard and pull a 44 or 9inch out of a truck from the 70's with 200,000 miles and the gears will be just fine. That said, over a long long period of time, you may see it, but in the typical 10-20 year life span of a truck, it wont make any differance. Same is true with all other parts in the system.

Lastly and very simply, if it was a bad way to go why would all the major auto manufactures be going to this system?

While manual locking hubs are 'nice' they are no longer needed in this day and age.

 

Easy to manufacturer and cheaper. The hub is one peice as opposed to many moving parts.

 

True, but if 5million of the 10million live axle Rangers came in with problems, you think they would be building them this way

 

Unfortunately I gotta disagree w/ you here Jay..
This is very true.. and ultimately why I believe Ford adopted such a system. Although in my opinion, it is only more reliable than the various types of automatic hubs. Conventional mechanical hubs likely proved too complicated for average consumers to use. (I have to drive back and forth?! How do I know they are disabled?!) The PVH system has a proven track record of being unreliable.. Live axles seems like Ford's last answer to the problem.
Not according to the EPA tests. According to those tests an '05 4x2 RegCab Ranger gets 18/23 MPG when equipped w/ the 3.0L V6. Roughly the same truck equipped w/ 4x4 gets you 17/21 MPG. Given, not a huge difference, only 5-10%. And some of that is related to weight of the 4x4 drive system. But the drag just has to hurt too.
I dunno how comparing a D44 or a 9" axle to what the Ranger uses is fair. Those are Heavy Duty parts.. I expect them to last longer regardless of how they are equipped. Also, aren't most HD vehicles (even the modern SuperDuty) equipped w/ locking hubs. I thought the Ranger was one of the few vehicles equipped w/ live axles. I always figured it was because of the target market: people who favor conveniance and econnomy over durability.
Define 'bad'. Is it worse than manual hubs, yes, in many ways. There just has to be an efficience issue. And it very obviously will lead to greater wear. Not just on the internals like the diff, but also on the CV joints and inner bearings. On a vehicle w/ manual hubs those parts would see less wear.

However it is far better from a usability perspective. There's nothing to use.. therefore people can't use the system wrong. I'm willing to bet that in the old days of manual and automatic hubs (pre-PVH) Ford dealers would occasionally see someone unknowingly driving around w/ the hubs engaged! W/ the fact that what used to be a feature strictly for work-trucks becomming such a consumer option, I'm not surprised w/ the move. The next step is a full-time AWD system.. Ironically exactly what the Explorer, Escape and now Freestar are currently equipped w/.
I'd like the choice. Just like I was attracted to the idea of a manual t-case because it was (expected it to be) more reliable. I would expect a purely manual hub system to be more reliable and more efficient in the long run.. but then I'd have to inconvenience myself by climbing out of the truck in the rain/snow/ice/wind/mud and change the hubs myself. And we can't have that now, can we!?!

 

Exactly. Add maintenence issues in here too. On one hand they remove the expensive and complex issue of trouble shooting automatic/PVH hubs. On the other hand they (potentially) add more frequent CV and bearting replacement jobs. Win-win for Ford if you ask me..

 

If nobody dissagreed with me I'd think I was right.. lol

I'll give you that. A nice set of Warn's would be awsome, but how many vehicles come from the factory with them? The PVH system had reliablity problems, the electronic system before that had reliablity problems, the new live system does not have reliablity problems (on the hub end).

I'll give you that too.. but that 6% loss can be attributed just a easily to the transfercase drag and the added weight. It would be more fair to compare the milage of a 00' PVH to a 00 1/2' LA, but I doubt we could find that or care to spend the time...

I wasn't necisarily comparing the two axles.. just a bad analogy. How many D35 Ring and Pinions have you seen striped chipped or broken under normal use (read standard motor, not high HP) or just worn out?

While SuperDutys are equiped with manual hubs, the manual is only there as a back up. They are full auto hubs, untill they go out. Then the driver has the option to go out and lock them. This seems like a bad attempt to get around unreliable hubs on them. I have personaly seen a superduty locking hub expolde, and neither auto or lock worked.

How great is the wear realy though? Yes its true, moving parts wear out. But if the part is designed to move then the engineers know that and figure that as part of the equation. How often do you replace the U-Joints on your rear drive shaft? For most people the answer is never. Same is true for a Constant Velocity U-Joint. Keep it lubed (boot untorn) and they should last for the life of the vehicle, for most people.

Same here. I would love a full manual system so I could know for sure my 4wd was working. But we are not given that choice so we must work with what we have.


I always enjoy a good discusion with ya Bubba...

 

Heh. You guys are so smart. It's nice to actually be learning something on this forum anymore

 

Or more importantly.. how well would they sell? I think Ford saw the writing on the wall and realized whatever system they used, it had to operate from within the cab (ie 'push button') and it had to be 'shift on the fly'. I think the masses would have moved on to another brand w/o these features. Regardless of what we think..
That's a fine point. But there IS a measurable difference between 4x2 and 4x4 mileage. I still maintain that some of that is because the 4x4's are spinning the front drive all the time. It just seems logical to me. I doubt we'll ever know for sure though.
Before my first Ranger I owned a pair of FWD vehicles. My family has owned FWD VW's for decades. Worn CV joints were actually quite common. ... And quite expensive to repair. From what I've seen and read, we basically have a FWD car's front drivetrain on our trucks. This setup is low maintenence, but not 100% reliable. We will have to repair these axles and it will cost us quite a bit of money. How frequently we will have to do so is yet to be seen. I don't think the live-axle system has enough of a track record to know.

That said, my "service advisor" at the dealer told me that he thinks it's a more reliable system because it keeps the CV's in motion and keeps the rubber boots from drying up and cracking. He said he saw plenty of people that would use their 4x4 only in winter. They'd have the CV's pretty much stationary all spring, summer, and fall, then in the first snowfall they'd throw the switch, the hubs would engage and their contanimated CV's would break!

So it's possible that this system may actually be BETTER for the CV's health. I'm just not sure I'm buying that.. Like I said, time will tell. And like you say, I don't have a choice!

 

personally i like the live axle

here in indiana i could be driving alone and bam you see snow drifted across the road, and think wow im surprised the last 10 miles had been dry.?? your going 55-60 click it in it engages and after you have passed through it you turn it back off. were as with manual hubs i would either risk it or get out lock the hubs and go.

i will agree that the parts wear faster tho, my dads 98 f150 has had a cv shaft binding issue for the last year or so. hasnt got it fixed yet but it does humm like a mother and binds up every once and a while.

also wouldnt the live axle make it harder to steer?

even all the down sides to it i would still take it.

heck if we had manual hubs we could think of lots of things wrong with it and wish we had a live axle and vice versa.

 

True True

Yup.. the differance is there, but I'm sure we will never know the exact cause of it or how much each componant contributes.

Aprox 250bones to replace an axle. I learned that the hard way. But thats at an independant shop, not Ford.

Makes since on some level...not sure if I care to buy that either though. While I dont think it hurts the CV's to be constantly moving, I'm not sure about that whole boot deal...

That pretty much sum's it up..

So like I said, I made that How To to give us PVH owners an option to help with the unreliable hubs. As you can see it can be debated as to which system is easyest on parts, but for the most part, we dont have a choice.

 

a couple points- when not engaged the TRUCK does NOT spin the the front drive train it is all because you are rolling on it and the cvs are t he lve hubs then to the dff then to the driveshaft then the tcase, but what happens when you spin the rear tires? the fronts dont move so the truck desnt have to make any effort to spin the front and therefore its all gonna be weight difference causeing the gas mileage difference.

as far as manual hubs not needed this day in age, where are you from cause i wish that i could put manual hubs on. would have been the first thing i would have done. people would not just get up and leave ford if the didnt come out with a shift one the fly either. its a nce feature for soccer mms in a bad blizzard but most guys who have a sac like manual. AND YES hubs do explode but thats why you carry extras because its an easy couple minute swap.


And jay have you seen all the prblems some people have with their rangers?? you gotta admit ford kind of hurries ideas into production sometimes then doesnt give two ****s because the ranger is still their "steddy eddie" just because you havent heard of a major recall on it doesnt mean there isnt prblems

 

ive seen cvs in great shape at a JY for 25-50 bucks

 

With the live axle 4wd system? No I haven't seen any major problems with it yet. Yes Ford does rush and yes the Ranger does have some major problems. But in general the live axle is a good thing. The PVH's, now those were rushed and we all see what happened there...

Name one situation you have been in that the live axle failed but a manual would not have. THAT is my point that they are not NEEDED. Yes we want them, but why?

Ok, but Joe Schmoe isn't going to go JYing to find one and install it them self. I got a rebuilt one installed for ~250.

 

Most people I know w/ manual hubs lock them up for much of the winter. On or about the first big storm they lock the hubs, then leave them locked for the whole winter.. or at least until they go on a long trip w/ lots of highway driving. This way they have the best of both worlds. All summer they aren't spinning the axle and causing wear. All winter they basically have a live-axle setup and are ready for action w/o getting out of the vehicle.
Nope.. well, not significantly harder anyhow. You have a differential between the two half-shafts on that front axle. And the drive-axle part isn't connected to anything when the t-case is in 2Hi. This means that the front wheels are capable of spinning independantly of each other. Spinning one front tire just causes the (disconnected) drive axle to spin at the t-case. The other tire is untouched.

Jack up the front end of your truck sometime (both front wheels off the ground) and try manually spinning the wheels in 2Hi: one spins and the other doesn't. Do the same in 4x: one spins and the other spins in the opposite direction.

 

disengagement of 4wd is one case...

we want them because it gives you control over one more compnent. when lock my front end, I get to drive around with out noticed a daily difference with the hubs unlocked. when On a tral I can lock only one hub on purpose. when its snowng i can lock only one hub one purpose and not get a ****ty understeer. when something DOES go wrong with the hub i can slip a new one on and go.

just a couple reasons...

 

Dude.. Gil, not sure if it's me or not, but I'm having a real hard time reading and understanding your posts here.

Locking one front hub.. wouldn't that cause the diff to put all the torque to the 'wheel' w/ the least traction.. in this case the one w/ the hub unlocked. Wouldn't it just spin the half shaft and do pretty much nothing? From the front end anyhow..

Maybe w/ a locker or a spool up front.. but I would think it would eat the discs on an L/S and do pretty much nothing for you w/ an open front diff..

 

colin i was referring to having a locker or spool.

sorry lol.

 

Ahhh! "Now I see!" said the blind man.. When you said "When I lock the front end.." I thought you meant the hubs. I take it all back..

 

ah yes now i see the cloudiness of my pst LOL

 

Ahhh yes.. if you want to have a locker up front then selectable hubs are a must.. good point Gil!

 

wow thanks guys.. i have learn n read alot in this post.. now i can pass on my knowledge

 

heres my take. Ford adopted the live axle/PVH (yuck) for one reason. people are lazy and to ignorant to know what a manual locking hub is. a manual locking hub, IMO is stronger and better. sure it has more mechanical parts but its also the weak link in the driveline. before a universal joint breaks, an axle shaft breaks or a differental gear gets stripped the hub will break. they are EASY to work on, dead realible and provide, at least with me, added security.

plus people now dont want to get out and lock the hubs. they dont know what they are for and/or just want to flip a dial and go. thats fine for a pavement pounder but for me i want lock outs and manual transfer case. it was mostly a marketing idea to get more soccer moms and yuppies in SUV/trucks and outta the econo cars and mini-vans. my views are based on someone who will use there 4wd as its intended and will eventually break something or has done so already.

sure it may be cheaper to manufactor but its also easier to fix a lock out hub and the are quiet cheap to purchase. the do require a little matience and the ability to get out, bend over and turn a dial...some people cant do that in this obese world we live in.

ford had the right idea with a manual transfer case on the FX/L2s but they needed to go all the way. i personally believe it was more of a marketing idea then a manufactoring stand point...but again these are my views from an avid off-roader and old school tech person.

as far as the live axle and gas milage, it will reduce it by some, how much? maybe 1 or 2 mpg pending how fast its driven. and the wear and tear? well thats minimal because its not enguaged...