I bought me Ex w/ manual hubs already installed. Just to be sure I am doing things correctly when I go into 4WD... first I hit the button in the dash so the 4x4 light is on .. next I get out and swith the huibs from FREE to LOCK I then proceed to drive .. NOW here is my real question. WHEN I WANT TO GO BACK TO 2WD do I get out turn the hubs then hit the button in the cab then back up approx 10 feet OR do I hit the button in the cab then change the hubs back to free then do the back up ? I know this should be simple but I just have to ask..please ltell me your sequence.... I went to 4WD the other day no I have a wierd vibration on acceleration so I wondered if I did somethingto aggravate u joints ? thanks a bunch everyone !!

 

If I anticipate needing 4WD, I will lock the hubs before I even pull out of the garage. Then I just need to push the button when I get to where I need 4WD. This also means I can shift from 2H to 4H "on the fly" without stopping. When I get back on good road again, I push the button to disengage the t-case, but will leave the hubs locked until I know I don't need 4WD again, or until I get back home. With manual hubs, you usually don't need to back up 10 ft to get the hubs to disengage; that applies to auto hubs. With manual hubs, you may still have to rock back a little bit to release any pressure inside the hub so the mechanism will disengage.
In reality, it doesn't matter whether you unlock the hubs first or the t-case; they are separate operations that are independent of each other. It is still possible that you've aggravated a u-joint or something, but it isn't because you shifted wrong. With the t-case in 2H and the hubs in free, the front drivetrain (axleshafts, differential, and driveshaft) should be free of the wheels and shouldn't cause this new vibration. Take a few minutes, jack up each front wheel, and verify that the hubs are disengaging. Then I would check the u-joints on the rear driveshaft.

 

One thing to add though is make sure you're not running 4WD on a hard surface. The transfer case is not designed to take the stress if the front and rear wheels can't slip a little from each other. If there is a slight difference in tire wear or pressure or loading, the resulting different diameters will cause the wheels to run a different surface speed at the same RPM. If you were on a hard surface, that may be the shuddering you experienced.

 

Thank you gentleman, both of you.

I dont belive there is a engage/ disengage issue here and I am being very careful about the binding axle on dry surface issue. But a relative point non the less. Thanks.
So I can still shift "on the fly" so to speak ? So I dont have to make my girlfriend get out a switch my hubs every time ? haha. Wow. Because I definitely will be using 4WD a lot here in Tahoe. Is there a recommended speed tp perform this ? And I dont assume you mean it is ok to drive with the hubs locked at all times but rather certain days when it is more obvious weather ?
In regards to taking a look at the rear u joint(s) am I looking for worn metal ? In other words I am not sure what it would look like if it were very worn. I have seen a few posts that alude to changing these u joints so can I assume it is done " easily " with the right tools ? I know they( joints ) are relatively cheap at local auto pts stores.

thanks again guys,

DinT

 

With the hubs locked, you can engage/disengage the t-case at whatever speed, because, with the front and rear spinning at the same speed, they can lock together seemlessly. More importantly is considering road conditions. If it's slick enough to need 4WD, you need to slow down to a safe speed for the conditions. That's what I do. If you look around Tahoe, though, I wouldn't be at all surprised to find some who just lock their hubs in Nov and leave them locked until Mar/Apr.Checking u-joints is usually as simple as grabbing the driveshaft and shaking it to see if the u-joint cross wiggles within the end caps.