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Astro Van Vibration Sonic Booming Noise at 50 MPH My Story

931 views 2 replies 3 participants last post by  sixsix 
#1 ·
So back in the fall I hit a huge pothole in my 2004 Astro when I got on the freeway and sped to approx. 50 MPH there was a very bad vibration and loud sonic boom type low frequency rumble, kind of scary. My first thought was tire or wheel damage. I pulled over an inspected tires and rims nothing seemed damaged. After a few days I put the car on jack stands with all the wheels off of the ground I noticed around 40 MPH the drive train vibrated badly. Checked the rear wheel bearings, they seemed fine. I shook drive shaft seemed tight, checked transmission mount it was fine, springs and shock also were fine. :banghead: Decided to take van into a shop for service and inspection. I was told the motor mounts were shot, I went ahead and replaced them, I also installed new u-joints in drive shaft, the vibration stayed the same. One day I drove the van it seemed the vibration had worsened; I noticed the vibration began around 30 MPH then BOOM!!! The Drive shaft BLEW! (F%$K!! :screaming: ) the caps from the rear U-joint were gone the U-Joint straps were still attached to the rear yoke very odd... I happened to have a 2000 Astro Van I keep for parts so I pulled the shaft, thought it'd bolt in NO DEAL seems the Rear U-Joint Cap diameters were larger on the 2000 Astro had to hunt for a U-joint with 2 different size caps the MOOG #477 seemed to do the trick, couldn't get the old U-Joint out the shaft the caps did not provide enough clearance to be removed from the shaft ears once popped. I had to cut the U-joint out with a cut-off wheel, finally got the new Moog U-joint in, Mind you I was doing all this outside on the ice on a beautiful 13 F Michigan Day just effin' lovely... Buttoned everything up with my salvaged 2000 Astro drive shaft guess what NO MORE VIBRATION or SONIC BOOMING SOUND.. I've read several posts on this issue Bottom Line the driveshaft was bad... Perhaps the pothole bent it or shifted the balancer on it. I noticed no impact or flown off weights on the old shaft... but my mystery was finally solved… :banana:
 
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