Hi, and Merry Christmas/Happy Hannukah to those who celebrate those holidays! And a great weekend to those who don't!

I'm noticing that when in 4 high on snowy/icy roads (so no binding or anything), my ride feels like I'm driving on corduroy (vibration). Not extreme, but annoying.
My tires aren't that good, which is some of it (it is vibey when in 2wd, just not that bad, and at 42-47 mph). Probably not the whole issue, though....

Hubs locked in 2wd, no vibe. Engage 4H, the vibe starts at about 25-30MPH, and I can't go fast enough to see if it goes away with speed.

I worked the front drive shaft by hand...U joints seem to have about no movement among themselves in any direction. No movement with respect to transfer case or front diff. I locked the hubs, transmission in N, transfer case in 2H. I have IFS btw...I can hold the front axles (either one) and turn the front drive shaft about 1/8 to 1/12 a turn....is this normal?? That seems like 'slop'....what does that mean? (what do I have to replace, LOL).
I should go check the play when it's locked into 4H, too....will do that in a bit. I just don't know what to look for, kind of....

Thanks!!

 

More info: with the transfer case in 4H, I can only turn the front drive shaft 1mm or so back and forth before the front pass. side axle starts to turn. Front U joints seem nice and tight....

 

There is always some slop. the vibration maybe coming from the axles into the hubs. Shack every part that rotates, & look for excessive movement. have the tires replaced and balenced that will help you find the problem.

It might also be ball joints, or wheel bearings, I have done all of mine and trust me they were banging.

 

Thanks, S.P. Sadly, I have to keep the tires 'til spring (they are like 3 season street tires, real junk style tread but otherwise are in decent shape). This truck sat a while before I bought; probably ran the tires down and got some flat spots, something like that. I'm wondering if applying power to the front tires can make that worse or not.

Having them in to be swapped front to back (rotated basically) might get me a chance to have that diagnosed - you know how they're always looking for work and trying to sell you ball joints, etc etc!! I'd love to get all 4 off the ground to check ball joint play etc....

 

Just an update, maybe it'll help another noob diagnose this:

Got a hand in BEHIND the shield on the rear portion of the front drive shaft yesterday, where the double cardan joint connects to the T-case flange. When it's cold, you might skip doing this in the hurry to get in and out again - gotta grab it in there! Yup - shot! You couldn't move the drive shaft up/down on its own, tho - had to hold the back of that joint. Man, it is sloppy as it can be. Front U is fine.

Picked up a replacement rear section from a buddy (used, good condition. $20) and will install it when it's no longer -10 out (2 days). Hopefully that ends my front end vibe in 4x4.

Got some really nice 31"s on the way, will have them mounted in a couple of weeks