Check my logic - Part 2!

[TollKeeper]

Am I remembering correctly..

I need to take the front differential out of the vibration equation.

My thought process is to remove the front drive shaft, and drivers side CV axle. And if the vibration goes away, to just leave it as is.

I dont need to put a stub in the HUB? (I am already 95% positive on this one)

I dont need to remove the passenger side CV axle, as the disconnect will eliminate that for me?

 

[Reprise]

Pull the front drive shaft alone, to start. At that point, the diff no longer turns. Test drive.

If you still have the vibration, you can pick which side to pull first (or just pull both).

If you do pull the passenger side, I'd rip out the disconnect and intermediate shaft (or at least get a visual of the shaft), to eliminate that as a source of noise. I wouldn't leave the intermediate shaft held in only by the d/s diff for very long, so if you decide not to pull it, I'd reattach the disconnect. You can zip tie the actuator to the frame and plug the connector in, if you don't want the 'service 4wd' on the dash.

You don't need to 'stub the hubs', as far as I'm concerned. I've driven w/o front axles with no issues (but I did pull both). But try just the front drive shaft first. It'll be plenty of effort to get it out, as it is.

 

[Mooseman]

Only the TBSS uses stubs for some reason. Otherwise they are not required.

I'd pull, in order:
The drive shaft
Then the left axle. Now it truly won't spin the diff.

If you pull the right axle, the left one will still spin the spider gears inside the diff.

 

[TollKeeper]

So I pulled both front CV Axles, and the vibration remains.

I'm thinking rear Axle now, or maybe transfer case.

I'm sending it to a shop one my credit card clears up some space. Maxed out from building my computers.1100 on the server, and 450 on the wife's new laptop.

 

[Mooseman]

Did you check the U-joints?

 

[TollKeeper]

Yes, they were good.. Except for one, which I replaced a couple weeks ago.

 

[TollKeeper]

Needing to pick the brains of everyone. Been chasing a vibration on this Envoy for at least a year.

Here's everything I have done..

Replaced the tires with new Michelin
Road force balanced the tires
Complete front end suspension was replaced 2 years ago
Replaced both front wheel bearings 2 years ago.
New Bilstein struts 3 weeks? ago
Removed both front CV Axles
New front rotors and pads 2 weeks ago
New rear, rear most, u joint 1 month ago. Front was still good.
New rear rotors and pads 1 year ago
Replaced the rear wheel bearings and seals today
Verified it isn't the spare tire by removing it

Yes the dif is plugged at the CV Axles hole.

I may remove the front drive shaft tomorrow, but I seriously doubt it's going to solve the problem. Since the CV shafts are out, it shouldn't be spinning anyways. Front dif is still full of fluid verified today.

I also checked the lash pinion to main gear, and it's perfect. Surprisingly since this is the first time the dif has been opened since new. No there wasn't any forbidden sparkles in the fluid that drained out. It was clean, clear, and in great condition. I replaced the fluid 13k miles ago, about 2 years. Transfer case was also serviced at the same time.

No dents or scrapes on the rear drive shaft. I can pull it and send it out to get balanced, but the vibration isn't that type.

The vibration starts at about 40, and is very minor until you hit 60ish, then it's very noticeable and you can audibly hear it in the cab of the truck. It doesn't get worse as the speed changes, it just completely changes at 60ish. But it's not distinct, and it's sounds like it's coming from the entire truck, not able to say it's coming from any specific location of the truck.

Opinions?

Ideas?

Help!

Haven't been able to drive the truck for about 3 months now, maybe more

 

[Mooseman]

Wheels, rear axles and front hubs straight? Everything turns true by hand? Tried jacking the rear and running the wheels at speed to try and see the vibration? This could isolate the vibration to the front or rear.

At speed, have you tried throwing it in neutral and see if the vibration changes? Maybe RPM related?

I once had a vibration as you describe on the Saab which was at higher speed. Had the wheels balanced several times to no avail. Even thought the PO might have used balancing beads. Turned out to be the tires.

 

[TollKeeper]

I have not done the in air at speed thing. Had not even thought about that to be honest. Well have to try that. At least it's not a AWD model, or have traction control.

Axle half shafts were straight as I could tell, with no bearing grooves.

Rims were also visually straight, and balanced out with minimal weight.

Tires did not show signs of a thrown belt

I thought it was the tires originally, as they were old, Michelin Defender LTX/MS, and had 65000k miles. I replaced those tires with the ones that are on it now. So 2 sets off tires with the same problem would be amazing..

 

[northcreek]

I just can't stop thinking driveshaft, could it have been slightly bent driving over something ? or perhaps a balance weight flew off...

 

[TollKeeper]

Took out the front drive shaft, still have a vibration...

 

[TollKeeper]

I just can't stop thinking driveshaft, could it have been slightly bent driving over something ? or perhaps a balance weight flew off...

The tranny shop I had it at said it wasn't the drive shafts, of course this is the same shop that said it was the front differential... and since it is completely removed the the equation now, we know that's wrong.

It's possible, not discounting that... I'm just at a compete loss of what else it could be. I gotta wait until me ball joints come in, and I will reassemble the front end. This way I can use the 4x4 to pull it out/in garage when I pull the drive shaft. I have a local company my work uses for drive shaft work.

There's really only 4 things out could be at this point. The drive shaft, the bearings inside the center section of the rear dif, the transfer case, or the transmission.

 

[Mooseman]

And the rear driveshaft? The run with it on stands at low speed should show anything out of round.

Edit: What about the rear output shaft bushing? If it has a lot of play, it could allow the yoke to move around.

 

[TollKeeper]

And the rear driveshaft? The run with it on stands at low speed should show anything out of round.

Edit: What about the rear output shaft bushing? If it has a lot of play, it could allow the yoke to move around.

The shaft spun free and true, visually.

 

[TollKeeper]

Dropped it off at the 4th? or 5th? shop last night. They have good reviews and see what they come up with.

@northcreek - My boss seems to think the same as you, that when I reinstalled the U-Joint, it was 180 out... But his logic doesnt make sense because it was doing that before the U-Joint.

 

[TollKeeper]

Got a call from the next shop I tried.. The NEW Rearmost Rear U-Joint I installed is bad.. Cant phuckin win! But they charged to diagnose that. Since it was new, I never gave it a second thought.. I thought wrong! They even provided a video to prove it. Its a SKF U-Joint. Hopefully I can find the receipt for it. Its got maybe 100 miles on it.

 

[Mooseman]

Maybe during the install, the ears got spread out? That could happen while trying to break the injected nylon retainers. That happened to me once before I learned the trick of heating the ears to melt the nylon. Hope that's not the case for you.

 

[northcreek]

Rear U-Joint I installed is bad.. Cant phuckin win!

Sucks! but, glad you found it before really tearing into it. There has been some recent talk about the crappy U-joints out there. When I can, I buy vintage NOS ones in beat up boxes on feebay. Actually used one today on my MH project (OD delete).

 

[Mooseman]

I had good results with ACDelco on my TB.

Have heard of SKF's hub quality has gone to shit. Maybe the same for their other components. It's such a simple part.

 

[TollKeeper]

Maybe during the install, the ears got spread out? That could happen while trying to break the injected nylon retainers. That happened to me once before I learned the trick of heating the ears to melt the nylon. Hope that's not the case for you.

Can't be spread out.. the motion you are seeing is on the yolk with the straps. Gonna have to look at it when I get it home over the weekend and see what the story is

 

[TollKeeper]

Vibration is 90% gone. The C-Clips were manufactured incorrectly. The clips are supposed to be "X" thick, and they were "Y" thick, about 1/3 the thickness they were supposed to be. So after install, the centrifugal force pushed the caps out to the thin C-Clips, creating play on the U-Joint.

Now I got to take the DriveShaft back out to get it balanced.. Problem for friday.

 

[TollKeeper]

So back on this, since the Envoy is back to Daily Driver status!
So...
Took the entire front end out of the equation - Removed front drive shaft, Removed front CV axles
Replaced front and rear - rear drive shaft U-Joints
Replaced rear axle wheel bearings.
Rebalanced tires
Rotated tires
Put truck on jack stands, and put it in gear up to speed, and you can hear it outside the vehicle.

I am beginning to wonder if its the side bearings in the rear axle? For that I would send it out to a shop. Dont have the tools to set thrust and lash. Its either that, or something in the transmission (Torque Converter?) is out of balance.

As mentioned above, the Envoy is currently on daily driver status, until the Saturn is back from the shop, which should be late July. So I have to drive it in its current state until then.

Are there other things I am not thinking about?

 

[Mooseman]

Torque converter out of balance would do it parked revving the engine, methinks.

I'm thinking the driveshaft is out of balance.

 

[TollKeeper]

Once the Saturn gets out of the shop, I will have it sent out. Its a 2 day wait on those to get balanced!

I am thinking its in the rear end, but the DriveShaft balancing would be a LOT cheaper.. I seemed to feel it more when coasting.

 

[TollKeeper]

So just a preface... Weekend from hell...

Saab blowing the head gasket on Thursday
Friday tracking down U-Joints for the XUV, one U-Joint was seized in the housing, had to take to a shop to get that one out. Dinner afterwards was great!
Saturday went to my cabin in the woods for 5 hours.. I got a feeling I am going to loose it in probate court, family sucks. Just a stroll down memory lane. Left my laptop on accident.
Sunday went to get laptop, got half way there, and the shift cable on the XUV broke. Stuck in 3rd, and no way to reach under there to shift it manually. Turned around, got home and got that fixed.
Today, after work, I gotta go to the cabin again so I can FINALLY get my laptop.

 

[Mooseman]

When reinstalling the driveshaft, put some grease inside the yoke splines where the output shaft goes in. I know that has cured a thud coming to a stop.