70 mph vibrations

just looking for some input on why my 2001 4WD is starting to serious virbration at higher speeds. The weird part it doesn't do it all the time. Any input or suggestions would be greatly appreciated.

 

Tire balance? Might check to see if you lost any wheel weights.

 

My 2000 does it in a cycle at 65-70mph. About 45-50 seconds total cycle. I can just barely feel it starting to come on at the zero second mark mark, it is at its worst at about the 25 second mark and gone by 50 seconds. Over and over and over. Changed wheels and tires. Installed new shocks. Replaced the rack guide (which was real sloppy) and check ball joints and tie rod ends.

 

lift? stock?

I have a 3" lift had to install rear shims for driveline vibes. still had a vibration that felt like front end @50-70mph. just replaced front cv's and its completely gone. check tire pressure, tire balance, alignment, tie rod ends, ball joints etc. too many components to narrow down w/o knowing your trucks info.

 

Alignment issues?

 

Check the carrier bearing - that can give you intermittent vibes - you can checking the basics like bad wheel bearings up front (jack up front and check for play when shaking the wheel - there's tons of how to's on YouTube), worn / leaking suspension components, tires out of balance (rotate one front to the rear at a time to single out a potential bad one). Even the front diff can give you vibes when you're in 2wd since it's spinning with the ADD system. Luckily alignment won't give you vibes without having been bad enough for so long that your tires are out of round. A cheap go pro knock off mounted underneath your truck can give you good clues on what's vibrating the most to help isolate the problem.

 

I had (still have?? dunno, haven't heard or felt it lately) that problem and on my truck it's associated with the rear brakes. I found that the shoes on one of the rear wheels were adjusted too tight, making it really difficult to rotate that wheel. I fixed the problem by backing the adjustment star wheel out until the shoes just started to drag on the hub. The problem went away.

Unfortunately the problem returns every now-and-then. One of these days I'll pull that drum off and check all of the emergency brake actuator parts. I did my last shoe replacement about 2000 miles ago using (supposedly) high-quality, brand-name brake parts and one new drum. The shoes and drum were not Genuine Toyota parts, and maybe that has something to do with it.

 

Mine shakes from 65-75. Anything over or under is smooth but at that speed my gear shift and head rests etc shake.

 

Rotate and balance your tires. That fixed it for me.

 

If your alignment is out and your tires are unevenly worn, no amount of rotating and balancing will fix it.

Also - if the tires are old (5 or 6 years) this has happened to me, even with good balance and good tread.

Anyway - agree that it is most likely tires.