Hey guys, I had a post earlier related but have questions to guys have installed hubs and 4x4 actuators....

. I have an aftermarket knuckle and have chewed up a 3rd actuator (chews the hub side, not axle). But in looking it's as if the hub sits too far into the knuckle. Where the edges are and the actuator sits when engaged it can only ever grab a very small fraction of the hub gear = add power = strips the teeth. It's as if I machine the front of the knuckle to allow the hub to sit just a little over an 1/8" further in it will be flush and give the actuator that extra bit of bite over the hub teeth it needs and be 50/50 almost for axle and hub contact.

Long and Short can anyone tell me if on the factory the hub sits flush to that last little "ledge" on the inside of the knuckle (black part where you can see the steel hub have the gap)? My picture shows the gap I have which doesn't seem right. If it wasn't there the actuator would bite that extra 1/8" over the hub teeth and help stop this.

Thanks in advance guys!!! Before I machine down something that isn't broken. Or else I'll have to try and see a stock hub/knuckle to see if they sit flush.

 

Dumb question, is the actuator your fighting the side making the noise, if so replace the other side from what I have learned is the noisy one is the good one and just losing vacuum due to the other side dumping the vacuum cuz of failure. Hope this helps.

 

Who_Knows.......the noise I'm getting is the actuator on the Passenger side (which seems to be consistently getting the power to it) being chewed to pieces. I know what you mean when referring to the potential loss of vacuum causing the actuator to slowly be released even in 2wd --- thus clashing the gears but this isn't that unfortunately.

--- my problem is the actuator is not biting enough onto the hub teeth. These things don't have much width (IMO) to begin with, but I'm only catching the very 1/8" -- or less -- outer edge of the hub teeth with the actuator teeth. There is no physical way it can grab any more as we've tried everything since the hub is sitting that far down in the knuckle. So it goes in all perfect, but is only holding by a tiny amount = add power and it shreds the actuator teeth off.

- So if in the picture.....the hub could come back that last 1/8" and sit flush to that last black lip where the actuator plastic piece rides it looks like it would be dead perfect. 50/50 on the axle and hub when engaged = more grab = no more shredding. It is an aftermarket BDS knuckle so my thoughts are that it may just be out that 1/8" so if I machine the front down (everything still has clearance), allowing the hub to be that much closer to the actuator = problem solved.

I'm just wondering if the factory one's sit back that much for reference before I get crazy. Since to me it has too or this would happen a lot even with stock tires. It would make sense to have the axle and hub have an equal amount of the actuator riding on them.

 

This may help fellas. The red line indicates the "gap" where the hub, in my opinion, should be seated back that much further. That would literally make everything match up perfectly as there would be 50-50 amount of actuator on the axle and hub = no more stripping the outer edge of the actuator. Seem accurate?????

 

By power do you mean vacuum, if so maybe try checking both of them with a mity vac brake bleeder and see if both hold vacuum. If the drivers side is leaking its causing the pass side to part way be in gauged and ratcheting. May I ask when this all started and was anything changed to start this problem or did it start on its own, heck maybe through this Ill be able to learn as well.

 

Over about the last year and half bud. I've stripped out about 3 actuators...and partially wrecked one hub. Axle has always been fine since it's been getting most of the meat from that actuator.

I'm starting to have a theory though and we're going to test tonight using the truck with the axle off to see if the actuator is shifting at all during engine running operation.

What I think MAY be happening (not sure if anyone has encountered this), is that the solenoid/device that cuts the vacuum from the engine to the actuators may be faulty or leaking slightly. So when I engage the 4x4 it will allow the actuator to engage.....but is leaking just a slight bit causing it to not fully lock on to the hub. Since I know it IS going into 4x4 as I'd be slipping on ice, put it in, got some grip.

BUT, when I put some power to it.....of course the engine is creating more vaccum, allowing more suction through the faulty solenoid/switch = actuator pulls back slightly more, less gear to gear contact = strip the gears.

 

You got it all backwards sir. 1, the default for the IWE is no vacuum and engaged in 4wd. So if you have a leak it will be partially engaging when not in 4wd. 2 the engine creates MORE vacuum at idle and less at higher rpm. So 2wd vacuum is applied. 4wd no vacuum is applied by venting the vacuum out. I recommend you vacuum test ALL parts of the 4x4 vacuum system from the solenoid down towards the IWE and look for leas. My guess is you have a leak somewhere and when in 2wd the hub is partially engaged and chewing up the IWEs.

 

Yep that is right, if the truck isnt running the hubs are locked.....truck running in 4wd no vacuum to hubs.....truck running in 2wd vacuum at hubs pulling them in to free the wheels from the haft shaft. The reason its like that so if the IWE fails you have or supposed to have 4wd. Test the hubs with a vacuum source like a mity vac to watch the gauge, and one other test thats simple is to unhook the vacuum lines off the solenoid plug the engine vacuum side and go drive in 2wd and see if the noise is gone.

 

---- we're on the same page guys. I know the system works with no vacuum = IWE engaged = 4x4. Vacuum to the IWE disconnects the half shaft from hub = 2wd. So we're all good there, and I realize a leak in the system while in 2wd would cause the IWE to want to slightly engage = grinding and damage that way but that's not what I have going on. Mine is the opposite and I'm having issues while engaging it into 4x4.

Because it seems I'm tearing apart the IWE gears while it's in 4x4 --- and it looks like just the outer 1/8th inch ---- I have a theory that the solenoid which closes and blocks the vacuum (when you flip it to 4x4) is leaking/not sealing completely which is allowing there to be some vacuum still at the IWE and thus not letting it seat completely onto the hub, or when you increase the vacuum from cranking the power up it pulls the actuator slightly back and then strips it off since there is not enough bite. I'll fire the truck tonight, engage 4x4 and see with a vacuum tester if I'm still getting partial vacuum or not....and even hook up the actuator and watch it cycle.

 

But you would be right on the vacuum being high at idle..........however don't you build the MOST vacuum when under load, but moderate/lower RPM? I know when she's spinning full out your vac drops off but I thought your peak was when the engine was still working but at lower RPM --- correct me if I'm wrong there too though guys!

Either way --- tests need to be done to see if I'm still getting vacuum at the IWE when I'm in 4x4 so I'll report back.