If they couldn't find any indication, yet they claim separation is the problem, then I would take my vehicle to another shop. I still say an alignment is your best bet.

 

Based on everything that was changed on the vehicle (including what was done before and done by them) they stated that seperation was the only other issue they could think of. But not necessarily the problem. Ill schedule an alignment and at the shop will also mention my issue and see what they drum up for ideas. Any thoughts on the company Les Schwab?
I also noticed that there are a few different types of alignments (standard, thrust, and 4-wheel). Im thinking I should go for the 4-wheel, correct?

 

what about the rear wheel bearings? Jack up the rear & put it in drive &bring it up to speed slowly & see if makes a rumbling.

 

Hmmm.. I believe GunsOfNavarone nailed it! Hub issue! Good luck! step66

 

Seeing as the truck has likely never had an alignment, Im going to go ahead and get one done. That'll take care of that possibility (and the tires are cupping as well so hopefully that will help).

As for bad rear wheel bearings. Would they not make a whining or humming sound while driving? Maybe it's not noticeable while in the vehicle..And would a bad bearing last 10K miles if it was causing this issue?

As for a possible hub issue..I have had the front passenger side wheel bearing replaced twice (I believe that job requires a whole new hub assembly). So I am familiar with the symptoms of that wheel bearing going out. This is not acting of that nature. What should I look for to check for this 'hub issue'? Any ways to test for it or things to look for?

 

I just hit 200,000 in my '00 4x4 Blazer, and it has had similar problems for about 50,000 miles. Vibration at 50mph and up, it used to start at more like 65. Got my wheels balanced a few times, replaced upper and lower ball joints, wheel hubs on both sides ($50 each on Amazon rather than $100 each at Oreilly), and both CV axles. I can say with certainty that after replacing each individual part, they all needed replacing. But, the vibration is still there. Now I'm almost positive it is the front drive shaft-from the transfer case to the front differential. This shaft has significant play in it. Check this on yours! Get under it and shake that front drive shaft and see if it shifts around. I have not yet figured out on mine if I need to replace that whole shaft or rebuild the transfer case or what.

 

Would the front drive shaft be even turning when using only 2 w drive? Jim

 

If the vehicle is equiped with the NV236 (4-button dash switch), yes.

To the OP, were the tires road force balanced or just a general spin balance? Some tires can have vibration problems under normal driving conditions that do not show up during a normal spin balance. Road force balancing simulates the weight of the vehicle on the tire during the balancing procedure which gives a much more accurate balance.

 

Copy that swartlkk. I believe the tires only had a general spin balance. Ill have to look around and see if I can find a place that does a road force balance (hadn't even heard of that much until now). Im gonna schedule the alignment for sometime this week, and will check into the road force balancing as well. My trip begins sunday so hopefully its 1 of those issues!

EDIT: swartlkk...I should also mention that I do believe this is equipped with NV236. It has the push button 4WD if that is what you're referring to..

 

Got an alignment done and rotated the tires. I wanted to have a road force balance done, but go firgure...the machine was down. Vibration is still present. The front shaft (from t-case to front diff) has a small bit of play, but it doesn't seem concerning to me (but what do I know?!). Hmmm...