I have a 4WD 2000 Blazer that does exactly the same thing. I've had my entire front end replaced and it still shakes at 65-70MPH. The problem with all Blazers is not the tires, front end alignment, etc. it is an engineering design flaw. If you have a 4WD (not sure about 2WD), there are no springs on the front suspension. The shock absorbs some of the bounce but not all of it and that is the reason for having springs and shocks on the front suspension to begin with. Look at any truck or other SUV (Ford for example), all have springs AND shocks on the front suspension.

 

Design flaw... Just because you do not understand the suspension design doesn't mean it is a flaw... And just because you cannot find the problem with your truck doesn't mean that all of them suffer from the same thing...

For the record, there is a spring in the front suspension on the GM 4wd IFS trucks. Just because it is not a coil or leaf spring doesn't make it a flaw. The GM 4wd IFS trucks have a torsion spring which carries the weight of the front suspension. This system works quite well actually.

 

It seems funny to me that just about every Blazer 4WD model has the same identical problem regardless of what's replaced (do a google search and you'll see what I mean). For the record, my blazer doesn't have any type of spring in the front end. If you can find one, I'll take back everything I said. How many other 4WD trucks don't have springs in the front end? Tell me what the problem is then...

 

I still think it's a tire issue.
And where are you getting this info that "just about every 4wd Blazer has the same identical problem" which is this shake? I've NEVER had an issue with mine. I don't recall seeing make complaints here about it either, and there are a lot of 4wd Blazer owners here. I'm curious to see where you got this info from.

 

So you read a few disgruntle reports found using a Google search and you think that every vehicle like yours has the exact same problem... Come on! That is utterly ridiculous. You are awful sure of yourself though, I'll give you that... How could the suspension work without a spring? Try this if you really must, remove your shock and see if the truck rests on the front bump stops...

So where is this mysterious force that is holding up the front end... Take a look at the lower control arm. There is a long bar that runs from the lower control arm straight back to a cross member further back on the frame near the transfer case. This bar is called the torsion bar and is in fact a torsion spring that supports the front end. For further information about the torsion bar, its adjustment, and some pictures, please take a look in the Tech Article (DIY) section for the T-bar Crank How-To article.

Regarding how many vehicles there are on the road with this suspension setup, take a look under most full size independent front suspension (IFS) GM 4wd vehicles when you get a chance. GM has been building these trucks like this since the mid-80's.

So now that your missing front springs have been found, why don't you provide us some information about your problem and we'll see about putting some more of your misconceptions to rest.

BTW, I have moved this discussion into a new thread instead of pulling the OTHER THREAD into another possible direction.

 

Visual time!
The pic below shows what you are looking for. The bar running along the inside of the frame rail to you lower Control arm is the Torsion Bar. This provides your "spring" as it twists the bar. As it twists, the bar resists the movement, thus wanting to return to it's original position, like a coil spring under compression.

This pic is off our 1995 Suburban K1500. Love that truck

I'm curious about this, too. Our Bravada has NEVER had a shake issue.

 

Kyle...you pwn people so well. lol.

 

HO-LY COW! All I can say is

 

i've had my Blazer up to 90 MPH and nary a shake or vibration. It runs comfortably all day long at 70-75 MPH.

I think this OP has no idea how IFS front ends work. My GF's Dad has a 2003 Dodge 1/2 ton truck and wait wait wait.. it has torsion bars under it too! I know I just replaced a wheel bearing on it.

If he has vibration issues its more than likely a bad tire or a bent rim. A bad bearing will cause noise as well. But he says hes had the front end replaced. Possibly a CV shaft? A bit more information would be handy. A vibration at 65-70 is an idication of a balance problem. Also warped rotors will mimic a bad tire too.

 

Wouldn't that be only noticeable/more noticeable when he stops? My rears were warped, and I only got vibrations when I stopped.