gixer2000
Retrofit or Bust
Is It damaged somehow? I cant tell in the picture
4x4 not working
- Thread starter ninjafied
- Start date
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So I still have more problems along with the vacuum solenoid there is also a vacuum check valve not working. I have bypassed everything to get vacuum to the hubs but they are still locked. With or without vacuum the wheels spin with the half shafts. So now I'm thinking transfer case problems
Transfer Case doesn’t sound like your issue, at this point we know you have plenty of vacuum system/ hub function problems...
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Also you say you solonoid was cracked.... that might mean water got in your vacuum system and froze n cracked it, if water gets in the system it can corrode your hubs and they may be stuck half engaged half unengaged. Even if your system fails in an engaged or semi engaged position, it doesn’t mean your 4WD will work. Pull the lines at the hubs and see if they have vacuum at the end of the run...
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Ya so I just got it working had my truck in the shop with a heater blowing on it and removed the vacuum to the hubs and they engaged. Once I get the solenoid and check valve I'll run it with the whole system to verify the fix.
gixer2000
Retrofit or Bust
your headache is already helping someone else. And this is the reason I love forums
and we're done the solenoid fixed the problem. my drive home was much more enjoyable. i was again able to take off from a stop with power, and 4 wheel power slides so much fun.
thank you all for you help, total cost of the repair was $30
thank you all for you help, total cost of the repair was $30
deweysmith
Full Access Members
Not necessarily. There is a check valve that is supposed to keep them unlocked when vacuum is not present. There is certainly some leak-down, temperature change will cause it to lose vacuum, etc, but they can and do stay unlocked without engine vacuum.
Incorrect, the IWE solonoid vents it to atmosphere when the ignition is off, only stored vacuum is in the reservoir the hubs are locked.
When your engine is off, there is no vacuum supply. However, vacuum is still stored in a vacuum reservoir which is located behind the battery. This is possible because there are two check valves in the vacuum lines. One check valve is between the vacuum tap on the engine side and the IWE Solenoid, and the other is in this same line (T- fitting in between) between the IWE Solenoid and the vacuum reservoir. These are on the vacuum supply side of the solenoid. The vacuum control side of the solenoid goes directly to the IWEs.
Now, this stored vacuum is not used when the engine is off, because the IWE solenoid (located high on the firewall aft of the battery) is not energized, and so vents vacuum in the lines that go to the IWEs. The purpose of the check valves, then, is to ensure an adequate supply of vacuum to the system even when the driver commands full throttle, which would normally also deplete the engine vacuum supply. This will become important in diagnosis later on. With no vacuum to the IWE, a spring forces a geared locking collar outward onto the hub gear, which then locks the hub and half shaft together.
