Test drove a 89 B2200. Vibration???

So I test drove a 89 B2200 with 5 speed and 210,000 miles.
At about 5 to about 15 or 20mph the truck vibrates and shakes on acceleration then it smooths out. But it also does the same when decelerating at that same speed. And.....It "still" does it with clutch pedal fully pressed down. Or even when it's out of gear and no brakes.

Any thoughts what it could be?

Also, the manual steering box is a little loose. What options do I have to tighten it up or replacement box?

Thanks for any info!

I'd guess at a driveshaft u-joint with that many miles on it.

Look at the top of steering box there is a screw on top and there is a nut around it loosen the nut screw it in a little tighten the nut if still loose repeat

Sent from my Desire HD using Tapatalk 2

Okay, Thanks guy's!