hey guys
I picked up a used 2001 silverado, extended cab, 2wd, auto for a pretty dirt cheap price.
however my only concern with the truck is I get a fairly nasty vibration that comes on at about 20mph, gets to be its worst at about 30mph then fades away at 45 mph.
it doesnt matter whether i'm accelerating, decelerating or in neutral coasting.
it seems almost road speed rather then rpm related cause whether I gear down to increase the rpms or not it stays the same.
according to the guy...it started after he did the u joints and carrier bearing, he had a receipt for this stuff but I didnt exactly slide under to check

I'm gonna try check it out tuesday, i'm trying to think or get ideas on where to check first. could a knocked off weight cause a shake bad enough to rattle the dash?


doesnt this shaft have a cardan joint? i've never replaced one of those so is it possible he screwed that up when the u joints were getting done?

edit to add its got about 295,000 KM so thatd be.... 185,000 miles

 

So my bad. I thought it was a 2001 but its actually a 2000 so no real difference

 

Driveshaft might need to be balanced. Pinion angle could be off. Wheels need to be rebalanced?

Does the vibration go away after some driving? Mine vibrates pretty bad in the morning but goes away after a mile or so. I think it's the tires getting flat spots overnight.

 

so I threw it up on the drive on hoist and lifted the wheels off the ground with the suspension loaded and truck in neutral
I started out by checking the front end and everything felt tight, all the bushings were in tact. I checked the rear for any bad bushings or broken springs, all good.
I checked the u joints and they are in fact brand new. I didnt see any weights knocked off the shafts and the drive shaft seemed to move fairly freely, no binding or anything
I checked the center support bearing for any play and that was solid.
so I decided to drive the truck with the wheels up and right at 30mph the truck was vibrating.
I had someone hold the gas and I went underneath, the driveshaft was spinning perfectly smooth, no issues.
the way that I came out from under the hoist I checked the passenger rear wheel first and it was spinning nice and smooth.
I came around to the other side and MAN OH MAN!
that left rear tire was hopping about 3"!!!
the rim was spinning straight, so the tire must be seperated or severely flat spotted.
I'm going on Monday to pick up the factory steel wheels and other tires so once I put those on I'll know for sure if it was the tire causing the issue