2002 astro vibration/shudder problem

[John4]

Join Date: Oct 2004
Posts: 59


Re: 99 vibration ?
Check out this story. I hope it helps Aloha, John4.I changed the left rear axle bearing and it cured the problem.The bearing did not show excessive wear and there was no play in the axle. The bearing did show signs of excess heat. It appears that the bearing got tighter has it warmed up. Hope this can help someone with a similar problem.

[bstout1]

I have similar problems with a 2001 Astro 2 wheel drive. Have replaced shocks and had multiple attempts to get tires balanced. The vibration seems to be from the rear tires and is present between 65 and 75 MPH. Shifting into Netural and varying the engine rpm has no effect on the vibration. Also, no change if driving with or without overdrive. Vibration seems to get worse when transitioning from level coast to slight acceleration. After rounding long slow curves the vibration will change slightly as the tires change to a differeng rotation relationship with each other. Seems like when an imbalance of both rear tires are in synk with each other, the hop gets worse. The tire hop is severe enough to cause vibration throughout the van and does not seem to be from the front end at all.

Just returned from Florida where the roads were very smooth and the vibration was very noticable. My tires are Uniroyal Tiger Paws with less than 40% wear. The tires do not show any delamination or brusing problems and have been rotated and balanced every 5 to 6 thousand miles. They were rotated and balanced just before leaving on vacation to Florida.

The tire hop is enough to make the vehicle seem a bit unstable around 70 mph. I am heading back to the tire dealership tomorrow morning since I just returned from my Florida trip. This is my 3rd Astro and I did not have this problem on the earlier 94 and 96 Astro's. I have 70,000 miles on my 2001 Astro.

I did replace the front rotors and the bearings were repacked as well as new brake pads installed. No change to vibration.

I have noticed that the tire dealerships all seem to be using a very slow rpm balancing machine.

I will be interested in your findings and will post any findings on my similar problem as events change.

[budscuz]

It could be engine. Try driving in each gear, run up the rpm. Uphill under power or downhill, coasting may give a clue if it's tranny or driveline. My initial suspicion though is an out-of-round tire if it's strictly high speed related.

[foxx4086]

give a thought to wheel bearings also.
cleaning and repacking the fronts is a cheap
try.
prehaps the rear bearings ?
something to think about

[Blue Bowtie]

Originally Posted by budscuz

It could be engine. Try driving in each gear, run up the rpm. Uphill under power or downhill, coasting may give a clue if it's tranny or driveline. My initial suspicion though is an out-of-round tire if it's strictly high speed related.

He's already tried coasting in neutral at 65 MPH with no reduction in the vibration.

[saturnguy2]

One mechanic I talked to seems to think it might be rear bearings, he said if it were anything in the front end I would feel it in the steering wheel rather than in the seat.
He said to leave it with him and let him look it over more carefully to see if he can figure out what it is.
I guess at this point I don't have much choice but to do that.

Thanks for all your help, I'll post the problem and the fix if / when I find out what it is.

[bstout1]

Originally Posted by saturnguy2

One mechanic I talked to seems to think it might be rear bearings, he said if it were anything in the front end I would feel it in the steering wheel rather than in the seat.
He said to leave it with him and let him look it over more carefully to see if he can figure out what it is.
I guess at this point I don't have much choice but to do that.

Thanks for all your help, I'll post the problem and the fix if / when I find out what it is.

That is exactly where I am now in working with AutoTire on resolving the problem. The only thing I can add about my 2001 is that the tire hop got worse after the last balance and rotation which makes me think the problem tire was on the front before and did not create as much of a problem there. So, it may be a combination of tire and rear bearing issue. Stay tuned...

Just got back from AutoTire and my problem is resolved. Turns out that both rear tires were only slightly out-of-round and the max out of balance was only 1/2 oz. This explains why my problem would come and go as the out-of-round conditions would only cause the severe vibration/hop when each tire was in a rotation alignment that resulted in the problem. AutoTire agreed to replace the two tires at 1/2 price. The new tires were balanced and we verified nearly no out-of-round condition. The van is now very smooth all the way up to 75 which is the fastest it was driven during a test drive.

[saturnguy2]

2002 astro vibration/shudder problem - When driving with the cruise control set at 70 mph the vribration/shudder is not constant all the time, it seems to come and go and various intervals.

Any new ideas as to what might be causing this problem would be appreciated.

[bstout1]

Originally Posted by saturnguy2

2002 astro vibration/shudder problem - When driving with the cruise control set at 70 mph the vribration/shudder is not constant all the time, it seems to come and go and various intervals.

Any new ideas as to what might be causing this problem would be appreciated.

That was exactly how my 2001 acted. I found that as I would round a long curve causing the back tires to change rotational relationship with each other, the vibration/shudder would come and go. I think the natural vibration frequency of the rear suspension on these astros can be excited by a simple out-of-round tire. Mine was not that much out-of-round but caused the rear suspension to go into a shudder response at 65-75 mph. I wish you were in the st. louis area and could try my new tires/wheels on your astro to see if that solved your problem. I now am running with no shudder at all. I had the problem for about 2 years and what a difference now.

[Blue Bowtie]

Originally Posted by Blue Bowtie

Inspect the tire carcasses closely for sidewall or tread bulges (I'm seeing this a lot more in new tires, and it is supposedly "normal") or signs of tread squirm.

If you can raise and securely support the vehicle and reach the same indicated speed, you may be able to determine if the tires themselves are at fault.

Originally Posted by bstout1

Just got back from AutoTire and my problem is resolved. Turns out that both rear tires were only slightly out-of-round and the max out of balance was only 1/2 oz.

That's what I've been seeing a lot more in the last 4-6 years. It seems that tire quality control has really been suffering unless you go with premium tires. The one-ply sidewalls really scare me, too. Check your tire markings - There are a lot more of those being made.

[captinhowdy]

my 88 astro with a 700 r 4 started doing this.and i was telling a buddy that rebuilds them about a shudder and he hooked me up with something called shutter Doctor it seams when you replace the fluid you lose the additives in the tork converter that are in it when its new and this puts it back.i put in the tube and 2 days later it stopped. it's worth a try. and that is my. worth

[GeoRandy]

Where do I find Shudder Doctor captinhowdy, and hey saturnguy2,
I have had 3 Astro/Safari vans and they all have done the same thing. At 65mph they started vibrating exactly as you and others have described. On my first 1995 van, I had everything checked out; driving in 3rd gear instead of overdrive, neutral coasting, balanced tires, checked for out-of-round, alignments, new set of wheels (twice), shocks, bearings, new(rebuilt) transmission, changed driveshaft....nothing seemed to fix it. Like my 1985 Safari, my 1992 Astro did it too (i junked them both, took'em across the scales) and now my 2005 Safari has started doing it at 80,000 miles. One thing I noticed about the 2005's and newer is they don't have nearly the tight turning radius of the older models. GM put 16" wheels on them starting in '05, instead of the 15" wheels they used to use on the previous years. I'm really displeased about the larger turning radius but thought GM might have done this as a trade-off to eliminate the shaky vibration problem of the '95-'04 models at 65mph and above. Obviously that was just wishful thinking on my part. The only way I knew to find out for certain was to buy one and hope for the best. So much for hope. You'd think I'd have learned not to buy these problems. The 4.3L,V-6, is a workhorse that pulls well and gets good gas mileage, although they do start smoking after about 200,000 miles even if you are religious about changing the oil and filter every 3,000 miles (I did and still do). I'm going to take it in to the dealership and see what they can figure out. My 2005 Safari is from a different dealership than my others and maybe they are more savvy. Let's hope. If not, I'm going to trade it in on something else. If you ever do get a fix, please post it. I still think from all I've done and read about this common problemis that it is probably the front ball joints/tie rods or a matter of replacing the entire front end. Ouch, on the whole thing.
Again, keep posting developments, I'll post what I learn, if anything.

[saturnguy2]

This is the 4th astro van that I've owned and the only one that I've had this problem with.
The local garage told me that one of my tires had excessive runout and needed to be replaced. He said that was what was causing the vibration.
I have not replace the tire yet but I probably will, I have nothing to lose.
If this does not solve the problem I will trade it in on a pickup.
GM made the right move when they discontinued the Astro van, it's not often that GM does anything right.

Thanks for the post.

Originally Posted by GeoRandy

Where do I find Shudder Doctor captinhowdy, and hey saturnguy2,
I have had 3 Astro/Safari vans and they all have done the same thing. At 65mph they started vibrating exactly as you and others have described. On my first 1995 van, I had everything checked out; driving in 3rd gear instead of overdrive, neutral coasting, balanced tires, checked for out-of-round, alignments, new set of wheels (twice), shocks, bearings, new(rebuilt) transmission, changed driveshaft....nothing seemed to fix it. Like my 1985 Safari, my 1992 Astro did it too (i junked them both, took'em across the scales) and now my 2005 Safari has started doing it at 80,000 miles. One thing I noticed about the 2005's and newer is they don't have nearly the tight turning radius of the older models. GM put 16" wheels on them starting in '05, instead of the 15" wheels they used to use on the previous years. I'm really displeased about the larger turning radius but thought GM might have done this as a trade-off to eliminate the shaky vibration problem of the '95-'04 models at 65mph and above. Obviously that was just wishful thinking on my part. The only way I knew to find out for certain was to buy one and hope for the best. So much for hope. You'd think I'd have learned not to buy these problems. The 4.3L,V-6, is a workhorse that pulls well and gets good gas mileage, although they do start smoking after about 200,000 miles even if you are religious about changing the oil and filter every 3,000 miles (I did and still do). I'm going to take it in to the dealership and see what they can figure out. My 2005 Safari is from a different dealership than my others and maybe they are more savvy. Let's hope. If not, I'm going to trade it in on something else. If you ever do get a fix, please post it. I still think from all I've done and read about this common problemis that it is probably the front ball joints/tie rods or a matter of replacing the entire front end. Ouch, on the whole thing.
Again, keep posting developments, I'll post what I learn, if anything.

[4sight]

Perhaps a bent or dented drive shaft?? Hit any debris on the road lately??

[saturnguy2]

I finally solved the problem of the vibration in my 02 astro van.
It turned out to be an out of round tire. The way I found out was to have it balanced on a machine that checks road force and also checks for out of round conditions of the wheel and tire. Most shops do not use this type of balancer.
Anyway, once the problem was found, I had the tire replaced and it cured the vibration.
From now on I will have my tires balanced on a top of the line machine.