Ok well I have a 2004 and its got manul shift 4x4. While replacing my hubs upfront after 110K mi due to play I realized that the knuckles have the air inlet's on them for the vacuum pumps they are just caped. Also I had replaced the yellow vacuum o-ring in the hub as well. Well now I need to replace a lock up front so I am thinking that if I am going to replace the locks I might want to replace them with air locks. Isnt the locks ran off the vacuum pump? In theory coulnt I run an air hose from the vacumm pump to like a ball valve to pull the locks in and just shift the floor manually to have shift on-the-fly 4x4. Mainly want to do it because I pull a boat and get into some ramps that I need 4x4 for but done realize it till i need and then I have to get out leaving the truck on a wet ramp to lock them in. But I dont want to do it before the ramp everytime as if I didnt need it its a pin in the you know what. Thanks for any insite.


Ryan

 

No that wouldn't work. Its a complicated system of air management..Get some warn premium hubs and be done with it. The air system hub lock on these trucks hasn't been the best design..I would avoid going anywhere near it.

Dick

 

Thanks I wasnt sure how complicated it would be. I saw the nipple on the back of the knuckle and the wheels started turning. "If I could apply some vacuum then I would have shift on the fly with air lockers hmmm" It was a thought. I will probably just end up getting the Warn's. That was going to be my choice if I didnt venture into the air. Its ashame its not actuated with compressed air instead of vacuum. I have compressed on the truck to power tools and the train horns of course. :-)

 

They don't simply lock with vacuum. They switch from lock to unlock and back with different levels of vacuum. High vacuum engages them, low vacuum disengages them.

 

What aldridgec said. It uses a full vacuum pulse to lock and 1/2 vacuum pulse to unlock.

It could certainly be done. You could get some vacuum lines, a PVH solenoid for an ESOF truck and a set of stock auto hubs, do some wiring with some switches and have auto locking hubs.

I can't say whether it would be worth the effort to you, however.

 

I can, not worth it. If its snowing or in the forcast, lock'em before you leave. then, if you need 4wd, just pull the handle (anywhere up to 55 mph, IIRC). You have shift on the fly 4wd, just the manual style, and not electric. It doesn't hurt anything (but maybe a .5 mpg) driving with the hubs locked in when still in 2wd.

 

Yeah it is sounding like its not worth it. About the leaving them locked in and just pulling the lever at up to 55mph without hurting things... Its gotta wear your tires also more in the front with them locked in but not engaged with 4wheel when just driving around. When I am locked in and not engauged you can def feel the front tires fighting the turns here and there. Thought would be because its not a LSD up front atleast on my truck. I know I have the LSD in the rear but the front aint. So my next question would be how much damage or over working do you think that diff is doing when just driving around with the hubs locked in full time and should you know go faster then 55mph even if you dont have the lever engaged?

 

I've had my front hubs locked since sometime mid-November and I've done a lot of miles. As long as your differential, u-joints, etc are maintained you shouldn't have any problems.

The only thing having the hubs locked does is cause the two front drive axles, the differential and the front drive shaft to turn while you're driving.

 

If it was just a question of loosing 1mpg I would leave them locked in all the time even down here in fl until I needed it and then just pulled the lever but I belive it does cause more wear on things like your unitized hub needles. If you have the factory u-joints in the front axles then there really isnt anything to "maintain" in the frint end except making sure your diff fluid is at the right level. SO just wondering if maybe the output shaft bearing on the transfer case is made to spin at highway speeds things like that. Not sure how its lubed. If its splash lubed from the transfer case gear spinning then if you arent locked in the cab its not spinning and in turn not lubing that output bearing but its locked in with the hubs so its still working. Those were the things I was wondering about the output shaft and the wear on the uni-hub needle bearing. While I was replacing both unitized hubs myself in the drive way with timkin untized hubs I became familure I think with where the stress points would be from a visual stand point atleast. Just things to think about. Also again its going to wear your tires I think since its not a limited slip diff. When I am locked at the hubs but NOT in the cab the steering is def tight and the tires are fighting one another. So the diff would have to be an open diff. That would be a good deal of work on the pinion for ever day use I think. If you were up north in the snow then maybe not so bad as its going to give on the ground much easier. But down here in FL the ground aint giving thats for sure.

 

Your outer front axle u-joints should have grease fittings on them. Beyond that, there isn't anything other than the differential fluid that needs to be changed at the defined intervals.

As far as the transfer case, both the NV271 (manual) and the NV273 (electronic) use pump driven pressurized lubrication, so I don't think there is any problem there.

The front unitized hubs are going to turn whether the hubs locks are locked or not, that is what they do. The internal needle bearings that carry the axle shaft through the hub are actually turning when the hub is unlocked. The hub is turning, the axle is not. When the hub is locked, the hub and axle are turning together, so there is then no movement in the needle bearings.

The fact that the front differential is open is actually a good thing. If it were limited slip it try to prevent the front wheels from turning at different speeds when cornering. An open differential does not do this.

You say that locking the hubs causes tight steering. The only thing that I'm aware of that could cause this would be the outer front axle u-joints not moving freely. You should not feel any difference in steering with the hubs locked vs unlocked when the transfer case is disengaged. I know I don't.

Since you live in FL I don't see any reason to leave them locked all the time. Like I said, mine have been locked for nearly 2 months now, but I've been using 4WD more often than not during that time. However I do not think there is any problem running with locked hubs as much as as anyone feels they need to.

 

Thank you for the info on how the transfer cause is lubed. My front u-joints do not have greese fittings on them for sure. I inspected them while doing the front uni-hub swap. They had no play in them and had pleaty of movement. Its not that the steering gets really tight its just that I CAN feel a difference. None of my rear drive shaft u-joints had greese fittings either until I replaced all three in the back. You are right with me not needed 4wheel all the time down here. I mainly just need it at the boat ramps. I fish the flats and when the tide is out sometimes the ramps here can gain an extra 30ft long. So imagine you have to put your tralier in so far to get the boat to be able to on it that the water is just about up to your diff. I wont sink my diff. So when you go to pull it out the trailer is in sand with the weight of the boat on it (3k) and your truck is sitting in alge, It can get tough getting it out sometimes. Still not going to leave my hubs locked in.

 

Wolfee,

Since you have to stop and unstrap the boat, and other misc. before you launch, add locking in the front hubs to the list of SOP. Once you launch, leave the hubs in while parked and then when you retrieve the 4 X 4 is available from the cab if needed. Unlock the hubs while securing the boat after retrieval and down the road you go.

The ESOF system is unreliable as the trucks age and a lot of guys abandon them when they have to rebuild the front end anyway. In Florida, the chances of needing on the fly 4X4 is directly proportional to the amount of off roading you do. By the sounds of it, your off roading amounts to launching a nice sized boat.

Post some pics of your rig and the boat, it sounds like a nice set up.

 

Thanks for the info I do just that leave the 4x4 engaged while parked at the ramp. I dont do mudding. I use this truck to take the toys to the fields but it does see the dirt field here and there. I have alot of friends with swamp buggies and trax and all that stuff so I let them beat up there rigs. My 8k pickup aint ever going to be a mud bogger and a daily driver and I know this. I know some people do it but to do it RIGHT takes alot of $. If they got the 1200 lift and 40in tires and call it a day and ride around in a washing machine on the spin cycle and like that hey more power to ya. I have pics of the truck in my profile I will up load a few of the boat.

 

Added some of the boat to the Gallery!

 

Nice Boat!

I think your set up is the best the way it is right now. If you add the vacumn actuated hubs, you will be constantly trouble shooting a vac problem. This also interupts the climate control functions so you have to maintain the system to get your vents to work properly.