UH-OH Vibration problems over 40mph...UGH!

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UH-OH Vibration problems over 40mph...UGH! ...With resolution and question.

Hey Guys,
I have a 97 40th Cruiser about 165K on it. No lift or other mods. I know sac-relig. Either way. I left my truck in the garage for a month or so and when I started driving it again and went over 40 it had a bizarre vibration. The vibration only occurs when I am accelerating. If I ease up on the gas pedal it goes away but as soon as i press harder on the gas it is right there again.
I searched the site and it seemed that most people suffering this fate had worked on either the driveshaft, put in a lift kit, or something along those lines. Is this normal wear and tear. Anything I should look at. It has been a while since I packed bearings. Any great ideas would be gladly welcome.

Thanks,
Tres
 
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The noise.

I can feel the vibration through the gas pedeal and hear it. I only notice it when I am over 40mph, the gas pedal is being pressed, and the rpms are >2K.
Thanks,
Tres
 
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What about maybe engine mounts?

Hey guys,
This whole thing is really bugging me. When i am at 60 or so I lighten up on the gas to stop the RPMs from continuing to rise, just keeping them at 2200, the vibration and vibration noise stops. So the driveshaft is still spinning at high RPMs and the U-Joints are still spinning and so on and so on but the noise is gone. What do you think about a failing engine mount. How do I check those? Does anyone else have any thoughts?

Thanks,
Tres
 

inkpot

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Howdy! Bad engine mounts will usually show up most when you accelerate hard from a dead stop. That is when they are stressed the most. Is this a constant vibe, or does it come and go? I'm thinkin it's fuel or spark related, like a fouled plug, bad wire, or dirty injector. Could even be a small vacuum leak causing a lean run condition. Have you checked for engine trouble codes? John
 
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I would start with the easy stuff and rotate the tires, depends on the tires, leaveing the truck parked for a month or so could cause a "flat" spot on the tire. I had that problem when I had old 10 ply nylon tires.
just my 2 cents.
 

Squash

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Try this.
http://www.tirerack.com/images/tires/vibechart.pdf

Better yet place the unit on jacks and start removing things like the tires: Yes or No vibration

Remove one driveshaft: Better or same

If you remove calipers allow the unit to come to a complete stop before engaging the Park position of your tranny...

This may seem tedious but it works.

While it's jacked up, put the tranny in N and grease your U-joints, try to move them all the while checking for exessive u-joint play.

Good luck

And another decent link
http://www2.dana.com/pdf/RRMT0002-0704HRLR.PDF
 
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If the engine was missing you'd expect a CEL on an OBDII vehicle.

Oh, if only this were true. :frown:
I've run across a few instances where I've known there's a misfire on an OBD2 truck and the computer din't. Sometimes you can just feel it.
Computers (even Toyota ones) just aren't that good yet. Although, they do keep getting better.

But, I'd lay money on a tire imbalance being the most likely culprit.
Occam's Razor: It din't vibrate pre-sitting for months, and did after. Most likely cause: tire got a flat spot in it.
If that ain't it, I'd suspect fuel varnishing on an injector or a fouled plug. Modern gasoline starts to break down very quickly. Like 2-3 months. Less here in AZ. I've had fresh gas go bad in 2 weeks here in the summer.
If you're gonna store a vehicle with fuel in it, use a fuel stabilizer.
 
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Worst case probably being not enough diff fluid in the front. Or axle seals leaking and mixing your knuckle grease with your diff fluid. Don't panic just look and see. I would imagine this would make a noise while moving at any speed but would probably get worse during acceleration since it would sling the fluid away.

This could possibly break down the ability of your diff fluid to stay between your ring and pinion gears. This is probably not the case but I'd check the knuckles and see if they are leaking. This is an easy check, just look under truck for that Silver looking bell at the two ends of your front axle and see if there is a lot of oil/grease. There should be a little on the bell but not a lot.

Then the next quick check is to pull the fill plug on your front diff and feel inside. The fluid should be almost to the bottom of the fill plug hole. This part is in your Owners manual. Both of these are visual checks that can be done in about 5 minutes if you have a wrench, socket, or whatever to get the diff fill plug off.
 
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You guys are awesome.

1) going to check the easy stuff. Pull the plugs and look for fouled. Check air filter to make sure it looks clean. Checking OBDII for codes.

2) open Diff fill screw and check for adequate diff oil. Check knuckles for excessive grease/oil around the seals or dripping from the seals.

3) Check brakes for any abnormalities in the rotors and pads. While I am down there I will check the hubs for adequate grease etc.

4) Get tires rotated tomorrow.

I am a little nervous about the jacking it up and driving thing since it is at speeds >38 or so that I feel the vibration.

Thanks guys.

Tres
 
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If you are doing easy stuff do what anderaa13 stated above;
Pull one driveshaft lock center diff switch and see if vibe goes away. Do this for the front and rear shaft. Then you can isolate it to the front or the rear. Then rotate your tires and do above test again, if the problem has moved to the other axle then you know it's a tire/wheel issue.

Im having a similar problem just hasn't bugged me enough yet to check it. Also check out Landtanks WRITE-UP for an easy way of checking your front axle.

Good Luck!

[EDIT] Doh! You state you have NO mods that means, (unless PO installed it), you don't have a CDL switch. So you can't take shafts out and drive. You might want to buy one especially for this reason. Here is Slee's website with said item and description of use;
Slee - Electrical Switches
 
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I am a little nervous about the jacking it up and driving thing since it is at speeds >38 or so that I feel the vibration.

Don't be. If you have a level driveway, hard-surfaced, and 4 good jackstands, one under each axle end, and go about it carefully, there's nothing to be worried about.
Once it's on jackstands, open the driver door, stand on the sill, grab the A and B pillars and shake the everloving crap out if it. If it stays on the jackstands, it'll stay on them when it's running. :grinpimp:
 
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The Resolution With A Question.

So I didn't jack it up and run it. Still a little weiry of the one.

I did however do some needed PM stuff. Planning to hit the front axle rebuild in a few weeks then the rear shortly affter.

I found the problem in the U-Joints. No great diagnostic. I just knew the service guys don't like to hunt for the zirks and the previous owneres....soccer moms don't like to get greasy...unless they are naughty. I like that type of PO.

Either way I replaced the front driveshaft's u-Joints but haven't done the back yet since the front took me FOREVER! I couldn't get the dam races out. Lots of hammer pounding. Is there an easier way than pounding it through one way then removing the race then pounding the other side back trough? Please enlighten me before I tackle the back drive shaft.

Thanks,
Tres
 
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Is there an easier way than pounding it through one way then removing the race then pounding the other side back trough?

I destroyed a brand new uni-joint bearing doing that. The 80 joints are a tight fit. I brought it over to a buddy with a shop press and it was a 1-2-3 operation.

When I get around to the fronts they'll go back in the press.
 
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I totally don't understand what you are talking about. Who cares if you destroy the u-joint when you are removing it....You are replacing it. As for getting them in you can do it with a hammer and either a rod that covers the entire race or a 21-20mm IMPACT socket. Why impact because the walls are thicker and that gives you a better surface to push it in evenly. Be careful and you will not destroy it. Hold the u-joint straight so your races go in straight. But he is right the easiest thing is to run it over to a shop with a press for removal and installation. It is much faster. I did my rear driveshaft this morning and it came out well.

Thomas
 

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