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2001 Chevy Suburaban 1500 4x4 Vibration 70MPH


1500j

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2001 Suburaban 3.73 rear end towing package LT. No lift factory everything. Just put new tires on it as well. 212,000 miles.

 

Ive had a 70 MPH somewhat harmonic vibration that has been happening the past two months. Its comes on @ 65 peaks @ 70 and is gone by 74mph.

 

Ive done many things. I have had the rear U Joint replaced twice. Once by me and once after I took it to a driveshaft balance shop.

 

 

HERE IS WHAT IS INTERESTING!

 

If I take the rear driveshaft out plug the transfer case and run the Suburban as a Front Wheel Drive truck in 4x4 the vibration does not occur. It drives smooth as silk when in 4x4 with ONLY THE FRONT WHEELS PULLING the suburban.

 

Any guesses as to what it is???? Its killing me. I cannot figure it out.

 

I just had the driveshaft balanced and they put a new Spicer u joint in while they did it. They said the front one is in very good shape.

 

Thanks, Im new here so if this needs to be posted elsewhere. Let me know

 

 

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If you think about how fast that thing is spinning at 70 mph, it wouldn't take much - maybe a gram ... or a tenth of one ounce - to cause an imbalance. Even a chunk of mud would, if it could withstand that g-force. There is probably an imbalance in both the pinion and the driveshaft - by rotating them, you brought the imbalance to opposing ends, which will cancel each other out.

 

Sounds like that's something you can probably live with - well done. :thumbs::cheers:

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02sub,

 

I got my straps at O'Reilley's Auto Parts. They had a set there for $6.xx dollars. So far its great.

I will get under there tomorrow and check it again.

We leave for a 2000 mile road drip on Sunday. Glad I got it fixed before that.

 

It all make sense now, but never in a million years would I assume the straps were bad.

link:

http://www.oreillyauto.com/site/c/detail/PRE0/53010/01464.oap?year=2001&make=Chevrolet&model=Suburban%2B1500&vi=5015704&ck=Search_universal+joint+-+clamp%21s%21strap_5015704_659&keyword=universal+joint+-+clamp%21s%21strap

 

I still don't understand what you replaced. Can you upload a pic or explain further please

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If you go to the link I posted there is a pretty good picture.. There are 4 bolts and 2 steel straps that hold the rear U Joint into the rear yoke at the rear end. Those two straps were stretched out or wore and would not hold the u joint tight into the rear yoke.

Some rear yokes have a cast cap that holds the U joint/driveshaft into the rear yoke as well....post-133807-0-28375000-1414027765_thumb.jpg


I added a pic from the net showing a strap in place.

I put 2000 miles on last week without any harmonic vibrations like I had before.


post-133807-0-28375000-1414027765_thumb.jpg

post-133807-0-28375000-1414027765_thumb.jpg

post-133807-0-28375000-1414027765_thumb.jpg

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02sub,

 

I got my straps at O'Reilley's Auto Parts. They had a set there for $6.xx dollars. So far its great.

I will get under there tomorrow and check it again.

We leave for a 2000 mile road drip on Sunday. Glad I got it fixed before that.

 

It all make sense now, but never in a million years would I assume the straps were bad.

link:

http://www.oreillyauto.com/site/c/detail/PRE0/53010/01464.oap?year=2001&make=Chevrolet&model=Suburban%2B1500&vi=5015704&ck=Search_universal+joint+-+clamp%21s%21strap_5015704_659&keyword=universal+joint+-+clamp%21s%21strap

 

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Another question? How much support should the tailshaft give the front of the rear driveshaft? When I put my drive shaft into the transfer case it feels like there is extra play in the driveshaft.

Ive heard there is a bushing that supports the slip yoke. Should there be much play? Can the bushing be replaced easily ?

 

Please look at this video and let me know if the movement is too much

 

THanks.

 

 

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I've never seen or heard of straps wearing out - someone at some point in the truck's life must've failed to tighten the strap bolts, causing the U-joint to slam all over the strap for a while ...

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Kind of a final update here.

 

Got the right bushing for the transfer case from GM for $10. Part # 15665313

 

The bushing took 80% of the slop out of the slip yoke going into the housing. In the video you could see it move. Now it does not flop in there as much.

 

The old bushing did not look too bad, it measured may be 10 thou wore at my best guess.

 

This cured 98% of my vibration now. Id say Im good to go again.

 

Thanks

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What is making the clunking noise while you push on the shaft? There is a bushing in the extension housing (or whatever it is called on a transfer case) and will usually have some play in it. The spinning slip yoke will float at speed. About the only time I have seen an issue with the bushing was not being able to fix a slip yoke seal leak. Was not a big leak, but would leak past the seal when driving, and collect in the dust boot part of the seal. That car got a replacement extension housing simply due to bushing being on back order, and I had an extension housing from a wrecker transmission that I got to get the case for another transmission I was doing. Again, not a GM trans. My experience is on Chrysler auto trans.

 

If the vibration is down 50%, chances are you can actually live with it. Stop driving at 70 mph, and put it to the back of you mind. Right now you are unknowingly making it vibrate every time you drive it on highways. Sort of like that squeak you get in the dash, once you know how to make it squeak, you are no longer able to drive without it squeaking. And no one else can make it squeak.

 

The video still shows the original u-joint in the shaft. Either that or you know a shop that installs the u-joints with the injected plastic type stuff to make the locking rings. Usually when they get replaced, you heat the driveshaft with a torch to get that plastic stuff to expand and ooze out the little injection holes.

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What is making the clunking noise while you push on the shaft?

 

The clunking is the yoke moving up and down in the tail shaft. Its clunking in that bushing.

 

The video still shows the original u-joint in the shaft.

 

Correct, as mentioned above, I've only replaced the rear UJoint on the driveshaft. The front one is still factory.

 

Ill probably just live with it unless I learn more about replacing that bushing. I think the bushing is cheap, it just getting it out of there.

 

I don't listen to the radio when I drive. So any vibration or squeak drives me nuts.

 

Nothing better than driving down the road in a smooth car/truck .

 

Thanks,

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Just FYI ...when I finished doing our '89 S10 Blazer's u-joints ... for the second time in 4 years ... I was surprised to see the nylon still in the fill holes. Even though both times I heated it fairly hot, the nylon still looked as if it hadn't been touched. Usually I need to get them so hot it all burns out of there, but that wasn't the case with this set. Just something for everyone else to be aware of.

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Just a note on something I said earlier.

 

The driveshaft slip yoke has a keyway in the splines. From what I read online this is actually a "vent channel" Its there to take the suction out of the fit, so it can freely move in and out and not turn into a piston compressing and possibly binding.

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Great topic and discussion. It's refreshing to read posts regarding mechanical issues when someone with a wealth of knowledge responds in a regular and extremely helpful manner.

 

Beats talking about window tint or malfunctioning infotainment systems any day of the week.

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Kind of a final update here.

 

Got the right bushing for the transfer case from GM for $10. Part # 15665313

 

The bushing took 80% of the slop out of the slip yoke going into the housing. In the video you could see it move. Now it does not flop in there as much.

 

The old bushing did not look too bad, it measured may be 10 thou wore at my best guess.

 

This cured 98% of my vibration now. Id say Im good to go again.

 

Thanks

Thanks for the reply!

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I've never seen or heard of straps wearing out - someone at some point in the truck's life must've failed to tighten the strap bolts, causing the U-joint to slam all over the strap for a while ...

 

Same here. Can't see how they would ever stretch on their own. The only way I can think of is that at one time someone had all the shafts out and swapped the straps by not knowing to keep parts where they belong, so no swapping occurs. With these being loose, that would make the other spot that uses those straps are going to be tighter than they used to be. If the OP has the old straps still, and feels energetic, he could swap the straps with the other location that also has the straps and see if the straps are now the right size.

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