Are there problems/disadvantages with ADD hubs? Interested in a '98 with 2.7 5spd w/ADD hubs. Presently own (3) yotas (88, 88, 94) all with manual hubs no problems at all. Thanks in advance

 

Other than the face that the cv's spin in 2WD? That's a huge disadvantage.

 

Advantage of ADD hubs:

Convenience of being able to shift in and out of 4wd during poor weather conditions, without having to mess with the hubs.


Disadvantage of ADD hubs:

Should you break an axle, you MUST replace the axle before moving the vehicle. The outboard joint keeps the hub together, and leaving the stubb of an axle sticking out of the outboard joint is not an option, as it will be turning.

The axles are always turning, thus more wear on CV boots and drivetrain

The drivetrain is somewhat of a drag on the rest of the system, reducing the effeciency of the vehicle, less gas mileage.

If you choose to lift the front of the vehicle, you can only go so high, then the fins start to touch when the shaft is turning. When CV boot fins touch, they generate heat, and will cause the rubber to crack, and the CV boots will spill their guts onto the ground. Thus, lift is limited to maybe a couple of inches.



[Exploded ORS outboard joint]

Advantage of Manual hubs:

Should you break an axle, no problem, unlock the hub(s) and keep going. I have broken several axles, and each time, I was able to unlock the manual hub and drive home. In one case, I removed entirely the outboard joint, covered the bearings with a grease cap, and drove the rest of the trail (Chinaman's Gulch, Colorado) in 3 wheel drive. Another case, I broke my second axle in Pritchitt Canyon, Moab, and just removed the broken shaft from the inboard joint. This left the inboard joint in place, sealing the differential, and the stubb of the shaft sticking out of the outboard joint. I unlocked that hub, and continued the trail in 3 wheel drive. I didn't have to worry about the stubb flailing around hitting parts, because the hub was unlocked. I drove the 7 hours from Moab to Santa Fe, in this condition as well. Manual hubs are awesome!



[3rd Broken ORS shaft]

Less drag on the drivetrain

The front end can be lift higher, as the CV shafts will not be turning when you are driving down the road. They only turn when you have the hubs locked in, for trail use.

Just my opinion and my experience. Also, if you are going to go to manual hubs, don't waste your money on high-zoot (supposedly heat treated) CV shafts and joints, such as ORS and Newfields, just get a couple of replacement TACO shafts.

 

Or you could disassemble the joint like you have in the pic below and remove the broken stub and balls (and remove the whole cv axle assembly leaving the tulip in the diff) and drive on it, just can't do 4WD until it's fixed.

 

This is very, very difficult to disassemble. In my case here, the cage snapped, and bearings were shot out under the pressure of Rocker Knocker, Pritchitt Canyon, Moab.

When installing a shaft into the outboard joint, its easy, you push the shaft into the outboard joint, and it snaps in place. When trying to pull apart, there is a snap ring on the end of the shaft that keeps the shaft from pulling out of the outboard joint. Take for example this picture:
http://www.hunt4steve.com/or/99_4run..._halfshaft.jpg

This Factory Service manual shows the shaft attached to the outboard joint. This is replacement from factory. Try and pull apart the outboard joint and shaft.....very, very difficult. Its much, much easier to just have a replacement outboard joint on hand, or an entire shaft to replace the broken unit.

 

This is a case, where you would want to keep an item such as this outboard joint. Should and ADD equiped vehicle break and axle, this outboard joint stubb (if its an outboard ADD stubb) can be put in place and the rig can be drivin out in 3 wheel drive.



The outboard joint will go into my tool bag when I'm on the trial. should I break my back up axle, I can put this guy in, and drive out in 3 wheel drive, or winch my self out. Why put this in? This outboard joint will keep the bearings clean from dirt and debrise kicked up by the tires.

 

ok, that is what I misunderstood. I thought there was a way to disassemble these like some of the other makes. thanks.

 

That is what I was talking about doing. What I want to do is find an outboard joint and just carry it around like you. alot easier than carrying aroung a cv assembly, in my opinion anyways. any idea where I might find one of those?

 

ever find out where to get an extra outboard joint stubb?? I wouldn't mind carrying around an extra.

 

Get the ADD truck if the price is right then convert it over to manual hubs, that way you can have the best of both worlds. If the conditions are probably warrant 4WD lock the hubs in, then you can enjoy the comforts of ADD.

I've been planning on going to manual hubs, but then a weak link is created on the shaft where the snap ring is located.

As for the gas mileage argument, the few people that I know personally haven't noticed a difference.