I drive a stock 4x4 1999 3.0L ext cab Ranger, I have stock rims with 16" Wrangler Silent Armors on them. Very nice tire btw, but anyhow, when on the highway my truck shakes at 74+. It's gets kinda bad and to the point where it's scary. When around 80 the vibrations ease off a litte bit.

Question is what gives? Why is the shake so bad? I know I have a good amount of weight on the front due to the 4x4 system, but should it be this bad? I just had new rotors put on not too long ago, so that's probably not it.

Any of ya'll got the same problem? I need help.

 

Sounds like drive train vibrations. First thing I would check is your u-joints, see if there is any play in the drive shaft, they are one of the most common parts to wear and cause a vibration like that.

 

u-joints, also get the tires balanced.

 

It means your truck is scared to go that fast. Find out what it knows that you don't!

 

I had the strange feeling it didn't like that speed either.....prolly scares the poor guy.

I do know one thing, I have to have a lower-end overhaul done. Something about something is causing it to wear in an oval shape causing it to cause the rear main seal to leak. I've gotta have the tranny pulled and all that and the seal replaced after you take off the flywheel and all that fun stuff. The brass bearings or something is being eat up as you can see fine glitter flakes in the oil when you let the oil filter drain. That and my valve sleeve(s)? is also worn out. You can here it chatter when it idles.
As you can see my dad told me all this fun stuff, I just don't remember his exact words. But hey, I'm a learning.

When all this is being done, I'll also have him check the U joints.