^ My thoughts exactly.
What you're most likely hearing is the transfer case engaging. But, that basically just connects your front diff gears to your transmission. If your hubs don't/aren't locked in (req's a good solenoid for auto ops), you won't have a connection from the diff/axles (which will spin b/c of the xfer case) to the wheel hubs/wheels themselves. Even with a newer truck, if you get water in the vacuum system there's a great possibility of it malfunctioning. Then, you end up replacing the vacuum solenoid, like JRLott was sayin, or you stick with manual hubs. Personally, I use alldatadiy.com for any actual issues, aside from tuning, that I have. It's insane how much great info is in there; especially for the price. You wouldn't want to carry around a Chilton with that much info. I can't imagine All Data wouldn't tell ya where the solenoid is located and the correct way to replace it; which should be pretty simple depending on location. I put Warn hubs on my ol 7.3. They were only manual so, I removed the solenoid in like two minutes and plugged the lines in another. Btw, the lines go to the hubs & if water gets in the solenoid, it gets in the lines, then in the hubs, & leads to premature hub failure. Just throwin that out the with the rest of this book.
- from farm to Air Force, from 7.3 to 6.7, still fairly new to PSA, diesel junky ever learning... "Life's hard, it's harder when you're stupid." - John Wayne ... I might screw that up once in a while, sorry if I do but, life happens lol
