transfer case vibration

[Bullet33]

I have taken my 2005 3/4 ton 8.1L w/4.10 gear suburban to the dealer to get a clunk noise taken care of. I thought that the problem was spring slap from the right rear but they said it was a yoke issue so they changed it and the clunk went away. BUT, now there is a vibration coming from the front that I feel at 61-65 mph. I have had the vehicle in 3 times for service and this last time, they said that they found metal shavings in the transfer case so they changed a faulty bearing in the transfer case. Previous repair attempts by the dealer involved balancing the driveshaft but still has vibration. This will be the fourth attempt to correct a vibration problem that did not appear until the dealer tried to fix the spring slap problem 3 months ago. Tires are not an issue. Has anyone else dealt with anything like this?

[Suburbia99]

Sounds like the same problem I am having. See my other threads on vibration.

My vibes come in at about 65-70. They will get worse under a load or accelerating. Disappear completely past 75mph. Does this sound familiar?

I am curious what the shop did to your transfer case. Which bearing did they change? I had a new output bearing installed (few years ago) and the vibration seemed to decrease dramatically, until a few years later (now), its as bad as ever.

My Burb is a 99 3/4 ton, 454, 4.10 Rear end.

[Bullet33]

My vibes start at 61 and continue to 65 with the worst of it at 64 mph.

They changed a large list of parts and I have not received the actual list yet. I took it back in for the 4th time and they said that now they are going to order a new drive shaft and install that. I do not believe that will take the problem away due to the fact that the problem is actually more prevelent in 4wd and "auto" mode. I know that there were 2 "carrier" bearings, a gear, and many more parts.
I will give you the total list after their 5th attempt to fix the vibration.

Originally Posted by Suburbia99

Sounds like the same problem I am having. See my other threads on vibration.

My vibes come in at about 65-70. They will get worse under a load or accelerating. Disappear completely past 75mph. Does this sound familiar?

I am curious what the shop did to your transfer case. Which bearing did they change? I had a new output bearing installed (few years ago) and the vibration seemed to decrease dramatically, until a few years later (now), its as bad as ever.

My Burb is a 99 3/4 ton, 454, 4.10 Rear end.

[corning_d3]

I don't think your transfer case is at fault. When a driveshaft is assembled BRAND NEW, it's balanced before being put on a vehicle. If you install a new yoke, the driveshaft could become unbalanced again. Take it back to the dealer and explain this to them, and demand a new driveshaft..

[Bullet33]

The drive shaft has been balanced twice as well as the tires have been load balanced. The suburban developed this problem at 9000 miles and now has only 12000 miles. I think they said that they put a nickle or some other materiel yoke on it.

Originally Posted by corning_d3

I don't think your transfer case is at fault. When a driveshaft is assembled BRAND NEW, it's balanced before being put on a vehicle. If you install a new yoke, the driveshaft could become unbalanced again. Take it back to the dealer and explain this to them, and demand a new driveshaft..

[GMMerlin]

Originally Posted by corning_d3

I don't think your transfer case is at fault. When a driveshaft is assembled BRAND NEW, it's balanced before being put on a vehicle. If you install a new yoke, the driveshaft could become unbalanced again. Take it back to the dealer and explain this to them, and demand a new driveshaft..

Replacing the driveshaft may not fix the concern.
You are correct that it may be out of balance..the best way is to system balance the driveline.

Here is the deal..first thing is to properly diagnose the concern by using an Electronic Vibration Analyzer and determining what order vibration is present and what rotating assembly is the source.
With that info, the source can be narrowed down...Vibration correction is an art that not many techs fully understand.
Knowing some of the ins and outs of vibration correction is critical for a sucessful repair.

[corning_d3]

Wow, there is someone else out there who's heard of this balancing method. Would i be correct to assume your a tech, GMMerlin?

[Suburbia99]

Yes, GMMerlin, I too have not heard anyone speak of using an Electronic Vibration Analyzer for a LONG time. It nice to hear that there is still some knowledgable people that exist out there in the automotive world. It seems every repair shop, including the dealers, are all alike. I am convinced that the ability to truly diagnose problems is lacking everywhere you go.

I am going to call around locally and ask about the system balancing and if anybody dignoses using the vibration analyzer.

Thanks GMMerlin for reminding me of this method.

To this point I have been thinking my driveline was not phased correctly (front and rear yokes lined up EXACTLY or 180 out of phase, etc.). I am even considering that the angles have shifted for some reason whether its bad mounts, shifted differential, bad yoke, etc. (search Google for Driveline angles and phasing). But now, based on what I have read today, I am curious if the entire drive system may need a balance check.

[RV'n Papa]

Sounds like I may have the same problem. My tow vehicle is a 1999 Suburban 2500 (454 and 4.10 gears). In non-towing situations,I am getting a strange vibration of the vehicle when decelerating in the 52mph to 67mph range. Above or below this range, I don't notice it. Also, when accelerating in that range, I don't notice it. The vibration is made known more as a noise than a particular feeling (e.g. it isn't coming through the steering wheel). The sound is similar to when a vehicle next to you is playing bass music very loud - sort of a "mrrrrrrrrrrrr" throughout the cabin. Also, I don't seem to recall the noise when towing. The tires have a good amount of tread left and the vehicle has 94,000 miles on it. Any ideas?

[GMMerlin]

Originally Posted by Suburbia99

Yes, GMMerlin, I too have not heard anyone speak of using an Electronic Vibration Analyzer for a LONG time. It nice to hear that there is still some knowledgable people that exist out there in the automotive world. It seems every repair shop, including the dealers, are all alike. I am convinced that the ability to truly diagnose problems is lacking everywhere you go.

I am going to call around locally and ask about the system balancing and if anybody dignoses using the vibration analyzer.

Thanks GMMerlin for reminding me of this method.

To this point I have been thinking my driveline was not phased correctly (front and rear yokes lined up EXACTLY or 180 out of phase, etc.). I am even considering that the angles have shifted for some reason whether its bad mounts, shifted differential, bad yoke, etc. (search Google for Driveline angles and phasing). But now, based on what I have read today, I am curious if the entire drive system may need a balance check.

You don't need an EVA for diagnosis...I'm old school and can still use a Reed tach to determine vibrations...like I stated, it's an art.
First thing is determining the source of the vibration..is it from the engine, drivetrain or tire/wheel assemblies.
There are specific frequency ranges for different sources and orders of vibrations...knowing this will aid in determining if this is a balance or possibly related to the u-joints.
You have obviously been doing some research to understand phasing and driveline angles, but you have to start with the basics first.

Every GM dealer has an EVA. Its just finding a dealer where the tech truely understands vibration correction diagnosis will be the key.
GM service information has extensive information on vibration diagnosis and correction and even a tech with no experiance can diagnose a difficult vibration concern if they follow the procedures outlined in service information.

[RV'n Papa]

Another way to isolate the problem is to drop the driveshaft to the rear if you have four wheel drive. Then run the vehicle in four wheel drive which of course will power only the front wheels. If you still have vibration, you have eliminated any driveline angle or phasing problems to the rear.

I may have isolated my problem by pulling a 4500 pound RV. The weight on the rear causes the vehicle to sit lower to the ground in the rear than when not towing. I don't notice any vibration when towing which makes me think the driveline angle has been affected by the weight. Maybe by lowering the suspension in the rear, I can correct the vibration.

[GMMerlin]

Originally Posted by RV'n Papa

Another way to isolate the problem is to drop the driveshaft to the rear if you have four wheel drive. Then run the vehicle in four wheel drive which of course will power only the front wheels. If you still have vibration, you have eliminated any driveline angle or phasing problems to the rear.

I may have isolated my problem by pulling a 4500 pound RV. The weight on the rear causes the vehicle to sit lower to the ground in the rear than when not towing. I don't notice any vibration when towing which makes me think the driveline angle has been affected by the weight. Maybe by lowering the suspension in the rear, I can correct the vibration.

Removing the drive shaft on some vehicles can cause damage to the transfer case if the vehicle is driven. Especially on vehicles with auto 4wd.
The recommendation is not a bad one and I have done this on some vehicles.
But lets not guess...lets do some basic diagnosis to determine what is going on.

[Suburbia99]

Thanks for the info GMMerlin.

It sounds like the I need to talk to the dealer. I will give it a shot. I have had such bad luck with GM dealerships that I am hesitant to make that step. But in light of this info I think I just might have to.

I will report back when I have had it checked out.

[Suburbia99]

Originally Posted by RV'n Papa

Another way to isolate the problem is to drop the driveshaft to the rear if you have four wheel drive. Then run the vehicle in four wheel drive which of course will power only the front wheels. If you still have vibration, you have eliminated any driveline angle or phasing problems to the rear.

I may have isolated my problem by pulling a 4500 pound RV. The weight on the rear causes the vehicle to sit lower to the ground in the rear than when not towing. I don't notice any vibration when towing which makes me think the driveline angle has been affected by the weight. Maybe by lowering the suspension in the rear, I can correct the vibration.

I first noticed the vibration two or so years ago when towing my 23 foot trailer. It was REALLY bad when towing. Not so bad without a trailer hooked up. It has progressively become worse over the past couple years. I hope to find out what to do very soon.

GMMerlin has some very good insight to diagnosing this. If I can find someone with a Reed tach (that knows how to use it) I would be in good shape. Im going to do some research on this in my area (Park City/Salt Lake Utah area)