Chevy & GMC Vans

Here's how it all started. The wife and I drove 1100 km in a snow storm to pick up our new puppy for our family. I was so happy that I decided to take the Safari instead of the Hardbody-it was horrible.

The van worked like a charm the whole way with no issues, other than topping up the PS fluid. The next day the wife took her brother for groceries, about a 45km round trip, and when she came home was complaining of a "shake". So I told her I'd check it out when I got a chance. Well I was changing the upper ball joint in my truck today when I got a fire call. I grabbed my radio, and I was enroute with the van. Til' I got it on the road doing 45 plus km/hr, and had to stand down because I thought the wheels were gonna fall off of the van. I ran a few test drives to figure out the problem. When I came home I jacked up the front and checked out the situation. I found nothing wrong-everything seemed nice and tight. I even tried the lugnuts, but they were tight.

During my test drive, I got it up to about 85km/hr or so, and when I slacked off to turn into my road- it was like I hit a rumble strip. Problem is, there are none around here. The vibration at that time was certainly something different that I had been feeling-with that being said, the rumble strip vibration is not something I can ignore. It was scary. It only lasted for a split second. Any suggestions?

95 AWD

If all of the front end parts are good I'd swap the tires. Front to rear.

Snow and ice in the wheels. Make sure they are all clean and test it.

LOL, I just came in from checking that. The wheels seem clean on the inside. When I got to the rear, I pushed back and forth, starting on the passenger side. I heard, clunk clunk clunk as the momentum got it rockin'. At first I thought it was the exhaust banging on something, but nope. So I went to the driver's side and did the same thing. I couldn't get that side to do it, but I certainly heard the other side. So, I returned to the passenger side, and physically grabbed the tire and pulled in and out. Each time resulted with a clunk. Went back over the the driver's side, pushed and pulled-same clunk.

Are the wheel bearings shot on both sides? If so, could this be the culprit?

I tried the same thing on the ol' astro, and it didn't do it. Now, the ol' astro is 2wd, and the safari is AWD-so I'm not sure if something is different. Should there be any play resulting in what I've described above?

Thanks for the quick replies

Yes, that clunk is normal. These vans have "c" clips holding the axles in the differential. The clunk you hear is the play in the "c" clip.

So you don't have ice or snow built up in the wheels. All your steering and suspension parts are tight.
Time to inspect your tires could have a broken belt inside causing the vibration.
How about your U-joints? Front axle shaft bad?

Well I was hearing some clunking lastnight when I was putting it into drive, but not so much in reverse. A buddy of mine stood outside the van to pinpoint the noise-and said it was definitly coming from midship to the rear of the van. So to me, that's u joints correct? I'm used to them making more of a metallic sorta ting when they're bad. These ones are more of a clunk sorta bang.

Either way, I'm picking up new ones today and changing them out. I hope that's the problem. I don't think there's anything else that could cause a clunk in the driveline is there?

Thanks

I missed this, but what you describe is similar to what I had when a u-joint went.

Well, I'm changin' them out today. So I'll let ya's all know how I make out.

U joint...likely. My toyota pickup blew two...exact same symptoms. But you should be able to wiggle the driveshaft back and forth and actually notice the play in the bearing...in any case, i bet that will fix it...

yep.. i vote u-joint(s) also

Yup, was it ever the u joints. Well, the rear one was the worse. The caps had no bearings left inside of them, and they were just "rollin on rust" LOL

Thanks again to all!!

Very appreciated

rollin' on rust... that would probably been worth a picture

LOL, I saved em'. I'll post a pic later on.....

yea my 95 astro awd van has the same thing going on it comes and goes when it wants but hapens between 40 and 80 km and feels like a wobble from the front right tire and make a thud thud thud thud sound till i slow down or stop then i can speed up and it goes away, i know the boot on the halfshaft on the same side is split the boot is the one furthest from the wheel so not sure if that would cause it, the wobble and clunking noise also stars after i hit a bump not all the time but some of the time .