CountyMounty

I am having a hell of a time figuring out my 4 x 4 problem. Conducted all of the test (except the check valves which I plan on doing tomorrow and everything checks out as it should, however my 4wd most definitely does not work, it left me stuck out hunting this weekend.

I may post more after tomorrow morning but hoping someone might see this tonight. My specific question is should the IWE locking gears move in and out when using a vacuum when it is not installed. Right now my IWE are still attached to the knuckle but are off the half shaft so and you can easily see the gears. The passenger side one moves back and forth as you apply/release vacuum. The drivers side one will hold a vacuum but it does not move at all when applying/releasing vacuum. To add more confusion I took the new one out of the package and put the vacuum test on it and it also held a vacuum but did not move.

I used the vacuum tester on the hose at the IWE connection site and I get a constant 20+" and no drop when reving engine. I am pretty perplexed at what is going on.

VTX1800N1

You found your problem. Yes, it should move. It's likely rusted solid inside. Are you sure you are applying vacuum to the correct side on the new one? It should be the large vacuum fitting. The small one is a vent.

CountyMounty

Wow what quick response. Yes I held the new one in my hand and with the vacuum on the large nipple when I pump it up it will hold vacuum 20+ but the gear collar does not move in and out like one of the two on the truck do. All of the other test I did other than the vacuum to each of the IWE after I separated them from the knuckle check out fine. Well except for one thing I just remember. I put the truck up on jacks all four corner and put in 4H and then 4L, in both I noted that my passenger side tire did not turn constantly and at the same speed at the others, it would lag behind, pick up. almost stop and then pick up again. This is the passenger side but it is the driver side IWE that the gear collar wont move under vacuum. See why I'm so confused?

So I see in several post that people talk about a bad seal with the IWE or the hub creating a problem but if I am understanding correctly the IWE will hold vacuum even then not installed or sealed at either end, as it is a closed diaphram in the IWE itself. I finally gave up for the day, my plan is to get up early in the morning and check the check valves. I traced all the lines and say now breaks or problems but haven't actually checked the check valves. I would have replaced the drivers side IWE to see if that fixed it but since it was my passenger side that seemed to be slipping on the engagement and also since the new IWE gear collar wont move I decided that might not be the right fix. Again thanks for such a quick response.

VTX1800N1

Sounds like the new IWE you got was bad. Take it back to the dealer and show them the vacuum test. They should replace it.

The reason you are seeing the front wheels behave like that is because the front differential is open. Power will go to the side with the least resistance, in this case the side not connected to a wheel- the driver side. I bet the driver side axle is turning, but the wheel is not. This is because that IWE is not working.

CountyMounty

The drivers side wheel was turning, along with both rear wheels at the same pace and response to throttle or brake, while the passenger side wheel did not always pick up or slow down the same and at times even failed to start moving for a few seconds or would slow right down. My 10yo actually noticed it first and said dad I dont think that tire is spinning the same and sure enough I tested it under throttle up and down and it did not respond to the same. The funny thing is that during the manual test where I turned the wheels/shafts by hand everything worked the way it should at both wheels. With the vacuum on the passenger side IWE now (separated from the knuckle) you can pump it and release it and see the IWE collar gear go in and out smoothly, but try it on drivers side it doesn't move at all but holds the vacuum. I am aware of the pat of least resistance concept but doesn't seem to be what I'm seeing here.

It does seem as though I might have got a bad IWE. I'm going to go ahead and replace tie rods while I have things apart so when I go to pick them up I'll take it with me and ask to test another one and see what happens.

CountyMounty

I'm wondering if the driver side one was stuck at partially engaged and the passenger side one was operating correctly if the drivers side would become the path of least resistance and get more power to it and thus turn constantly with the others (with it up in the air there would be not resistance) and the passenger side might get intermittent power as its fully locked. Not sure this makes sense though because partial engaged and full engage with no resistance free spinning in the air should be similar. I'll have to look more closely at the drivers side one in the morning, try to push it by hand and if it is completely stuck see if its at a point of partial engagement.

VTX1800N1

Even with both IWEs locked to the wheel, with both in the air you may only get one to spin. This is again because the front is an open differential. What's happening is that the spider gears in the differential are spinning around the axle on the side that I is not turning. The same thing happens if you have one front tire on glare ice and the other on dry pavement (assuming the rear tires are also on ice and so will not move the truck). Because of the open differential, the tire on ice will spin, and the tire on pavement will receive no torque.

CountyMounty

Ok that makes some sense and it might have got me on the wrong track thinking my pass side Iwe was the problem. I had something come up today so didn't get to it. But now I'm home and in the garage possibly pulling an all nighter cause I need to get things back together.

I just finished checking the whole length of the hoses and check valves and found that 1 of the 3 check valves, the ones just before the solenoid, is bad. You can freely blow air through both ways. Is it possible this is the only problem with the whole system.

I also removed both Iwe and inspected closer and see little if any wear on the gears.

CountyMounty

Alright got it all figured out and back together (well all except I still need to find a check valve somewhere. Eventually I was able to figure out that my problem was my drivers side actuator (IWE). I found out that my vacuum tester was not working right (as another poster mentions make sure your testing equipment works right or you'll be fooled). Actually it wasn't the vacuum pump itself but the L connection I was using on the end. If you pushed it on hard it would show anything had a vacuum (much like if you just held your finger over the end. Anyway once I figured that out I reduced tube size coming of the vacuum test pump and connected that directly to everything. I was able to find out that my drivers side actuator would not hold a vacuum. Also just a quick easy test anyone can do without a vacuum is to just put a tube on the actuator vacuum port and suck it in your mouth like a straw (obviously be careful and aware of sucking up nasty stuff). The actuator should move in and out as you suck/release, and you should be able to temporarily hold a suction on it.

Since I already had two new actuators and had everything all apart I went ahead and changed out both anyway. Put all back together and took it for a test drive on a nice frosty morning so was easy to test the 4x4 in a nearby grass field. It was a lot of work, diagnosing the problem and taking both sides all apart and replacing, but probably save $500 over taking it in to be repaired.

The OP of this thread and everyone's additions was great and made it possible for me, someone who is slowly taking on more DIY repairs, to get this done. Thanks to you all.

VTX1800N1

You're welcome.