hockey88fan

My truck has ADD hubs, so the cv axles spin at all times when driving, even in 2 wheel drive. If I switch to manual hubs, the cv axles wouldn't spin while in the free unlocked position, correct?

millball

They will not spin unlocked in 2WD.

hockey88fan

Ok, that's what I thought, thanks for the quick reply. So it seems there would be less wear on the cv axles, spindle bushing etc. Makes you wonder what the advantage to the ADD flange set up is over the manuals. I use 4wd a half dozen times a year, the inconvienance of having to get out and lock the hubs seems negligible.

scuba

Convenience.
The trend from free wheel hubs to drive flanges and ADD can be compared to the trend of auto makers producing more auto transmissions than manuals.

toyota4x4907

The "extra" wear on CV axles/joints with ADD is minimal at most under normal driving conditions. Plus like Scuba said just convenience due to market.

daved5150

iTrader: (1)

x3 on that...it's what keeps alot of Americans fat and happy...so they don't have to get off their butts and lock in the hubs. Kinda like when they can't take the shopping carts back to the store/cart area. I don't necessarily agree on the idea of no additional wear with ADD, because I'd rather have the CV's turning only whenever I needed 4wd. I know when I added Aisin hubs to my 94, she had more pull up the hill that I take to get to work as opposed to when the ADD plates were still on the truck. The 4 banger needs all the help it can get. I'm also getting rid of all the ADD vacuum stuff and going with a 1st gen axle tube on my IFS.

wyoming9

iTrader: (1)

I fail to see how stopping the front drive train from spinning would have very limited effect on wear and tear .

Any time one stops anything from rotating you are saving wear and tear.

I would like to know What Idiot come up this concept??

Myself I notice a big difference in the drag on my converted 92 4Runner between when the hubs are locked or unlocked.

So much so that I thought I was in serious need of a tune up or fuel filter.

Also gives one the option of driving a vehicle home with a front drive line failure compared to a ride on a rollback or trailer this alone is enough to do this conversion at least to me.

RJR

Unlike others on this forum, I don't think the ADD system was a bad engineering decision at all. As far as wear goes, lightly loaded parts running in clean lubricant don't experience significant wear. As I pointed out in another post, when I pulled my front diff apart after 193,000 miles to install the front locker, there was no detectable wear on any of the parts, even on the differential gears which had been spinning on the center pin that whole time. Same is true of the CV axles - the only reason I replaced them is because the rubber boots were torn. That's a condition of age of the rubber, not number of times they went around.

As far as drag goes, I think it's pretty insignificant. I put manual hubs on my vehicle because of adding the locker, not to save gas. I measured the torque required to turn the CV axles when in 2wd. It's less than 1 ft-lb. It takes about 125 ft lbs of torque at the wheels to move a 4runner down the road at 60mph. So, manual hubs vs. ADD would be about a 1% change in drag, which seems hard to notice. I keep pretty close tabs of my gas mileage on each tank, and I really couldn't spot the difference when I added the manual hubs.

To me, the ADD system is actually kind of elegant. I like the fact that the locking mechanism runs in the clean, well-oiled environment of the diff case, rather than in the more contamination-prone hub. The actuators are electro-pneumatic, which have high reliability. I think it's a good design, plus is indeed very convenient.

Just my thoughts...

Flash319

I run ADD with manual locking hubs. I live in a cold climate and running just the ADD seams to rob power. The cold grease and extra friction losses of turning the CV's can be felt when I have the hubs locked, especially with the 22RE. Maybe I just need new bearings in the hubs.
Just seams silly spinning up all that mass for no reason, not just the torque of getting it moving.. I leave the hubs locked mostly in the winter because I am in and out of 4x4 all the time but it is nice to have options when I hit the highway and in the summer.

One of the best mods I did. Also nice if you break stuff....

wyoming9

iTrader: (1)

Interesting two of us can feel a big difference one rocky mountains or flat lander .

2 on the east Coast

Temperatures should be around the same .

Well in any case just the added benefit of being able to disengage the front drive line was reason for me to put Warn Hubs on.