Chevy & GMC Vans

so i'm not sure where to post this but i have a vibration that i have never been able to get rid of it's all most not noticeable when accelerating except you can see the review mirror shaking a little bit starting at about 80km/h 50mi/h. If i get up to say 150km/h 90mi/h and let off the gas i get a fairly violent vibration, if i'm just maintaining the speed though you won't feel the vibration only when decelerating. I had the pleasure of making a rather short stop today on the highway and you don't feel the vibration under braking conditions. U-joints and prop shaft have been done recently, tires were rebalanced only days ago. i was watching the other vibration threads for ideas but i didn't notice anything that i feel wound cause this (i may be wrong though) i'm sorrta leaning toward front cv's but not sure what symptoms they would cause and would have to take them out to really check them (i think that's what i was told)

I had an old Javelin do that and it was the tie rod ends.

I would look at the idler arms. Failing that try looking at the output shaft of the trans.

I agree that the steering components are at falt. Tie rods, draglink, pitman arm, jack up the van and check them all. Don't forget to check your wheel bearings too.

Peter

wheel bearings were replaced 2 and a bit years Tie rods, draglink were replaced under a years ago idlers, ball joints were replaced just after i bought it 3 years ago (it been 3 years already...?) inspected 3? weeks ago and there was very little lateral motion. steering gear box is the only thing that hasn't been replaced yet but sure needs to be.

actually a couple weeks ago i had 30 24x24 paving stones in the back of my van and i was drifting back and forth on the highway like a real drunk. Especially after lane changes had to keep counter steering (actually a little scary) almost like a had a REALLY heavy trailer on me going down hill and it was pushing me around. not sure if that will help point to the answer or not but thought it might be relevant. i'll be up under there today or tomorrow so i'll take a peek at the idlers again since there are the oldest component in there. anymore suggestions are always welcome

Have you checked the diff pinions? You may have one that loosened up for some reason. The only way to really check them would be to remove the drive shafts from the diff's. If they check out, remove the front drive shaft completely and test drive.

Does it do if you put it into neutral at that speed?

hmmm i haven't tried it in neutral

edit:so i tested it this morning and even in neutral it's there also cruising at 85mi/h the vibration is visible in the dash 90+ mi/h you can hear the dash shaking and the steering wheel is clearly vibrating.

All the crap in your toolbox in the left rear corner of the van is throwing off the balance numbnut!!! Eh!

you listen here my 300lbs of random stuff is evenly spread out back there