08 Tahoe Vibration - SOLVED

[08TahoeVibes]

Hey Guys,

I have been chasing a vibration with no success that appeared out of no where in my 08 Tahoe LTZ and am coming to more intelligent minds than my own for suggestions/input.

Vehicle Details: 2008 Tahoe LTZ 4x4 with 165k miles (no lights on dash and no codes returned when scanned)

Symptoms:

• Vibration on both acceleration/deceleration (which prior to the first dealership visit was most noticeable above 77mph; it was observed at lower speeds as well ~40/45mph but at 77mph a passenger would identify that there was a vibration)
• Vibration is still present when putting the transmission into neutral at speed.
• Vibration is most noticeable on acceleration (for example; accelerate to 60, let off the gas, and the vibration is less on deceleration than it is upon acceleration).

I took it to the a local Chevrolet dealership for diagnosis and had their suggested work completed on it but the issue seemly is worse/more noticeable at lower speed than it was when I first took it in.

During this first visit to the dealership they:

• Replaced both Front Hub Bearings (technician noted that they were noisy and that the RF had play)
• Replaced A/C Belt (cracked)
• Total A/T Fluid Exchange
• Replaced Front Differential Pinion Seal
• Front Differential Service
• Front Differential Kit Service Synthetic
• Transfer Case Fluid Exchange
• Power Steering Kit Service

After that visit and noticing that the issue still existed, we took the service manager along for a drive on the highway and exhibited the same behavior as noted above. During this trip, it was observed that when power braking the truck that at least one of the engine mounts had failed.

During the second visit they:

• Replaced Both Engine Mounts
• Replaced Exhaust Manifold Gaskets and Bolts
• Replaced Exhaust Seals (2)
• Road Force Balanced All 4 Tires

Obviously a little defeated, I took it home after the second visit and wanted to rule out a tire issue (I believe this could be ruled out as the vibration subsides on deceleration) so I rotated the tires but there was no change in the symptoms after this. I checked for missing weights on both front and rear driveshafts and did not find any indication of any missing.

The truck was 99.9% of the time operated with the 4x4 selector in Auto but since having this vibration was switched to 2HI (and has been since before the first visit) in an attempt to rule out any complications there but the issue still existed. If I change the dial into Auto, I can hear the some engagement below the vehicle and nothing sounds bound up in the transition or anything.

It goes without saying that I am nearing my wits end on chasing down after already sinking a substantial amount of money into the fix. This truck has been solid with very little minor issues and shows that GM knew how to crank out quality even after a recession.

The only bad idea is no idea so shoot any ideas that you might have.

Appreciate any and all knowledge and experience for you guys! Thanks in advance!

 

[swathdiver]

Do you feel the vibration strongest in the seat or through the steering wheel? How old are the tires? Are the tires aired up evenly and is this test done when the tires are warmed up?

Leaving the transfer case in AUTO will wear it out soon enough. When was the last time all the differential and transfer case fluids were changed? When I got my truck, she bucked like a bronco until all the fluids were fresh.

 

[j91z28d1]

to me this is text book drive shaft vibration.

you're dealer is horrible at repairing cars. please stop going there and giving them money. it's so painful to read about. it hurts my soul how bad techs are these day.


don't try to repair what's in there, just order a new one. it's. pretty simple to install yourself. Just make sure you wheel chock it and be on level ground.

sadly I believe they are discontinued at gm. but seems Dorman will make you one, it will probably still vibrate just a touch, but nothing like you have now.


some guys say they have had luck with local drive shaft shops, but I never have. I've wasted years of my life over this crap. either oem or good shape from a junk yard is all over had luck with. sadly the junk yards usually move cars around with fork lifts and bend the drive shafts. so yoh gotta inspect well.

 

[08TahoeVibes]

Hey Swathdiver, thanks for the quick reply here.

I would say strongest through the seat. For example, if I have my phone on a vent mount above the radio, you can see the screen physically shaking with the vibration.

Tires were replaced back in November of '21 (~26k miles ago). Tires were checked and aired up to 32psi cold. Vibration is the same from the first part of a drive to the end.

Differential and transfer case fluids were both replaced within the last 150 miles.

Glad to hear that you got the bronco out of yours before it was too late (I'll be surprised to see any of those get to 150k+).

 

[08TahoeVibes]

j91z28d1 - thanks for the input and suggestion here. What color is your Z28?

Front driveshaft was/is the next thing on our minds as well. The dealer removed it from the first visit as indicated by marks on the bolts as well as chalk marks for indexing so not too afraid removing and replacing at home.

Does it may any sense/is there any harm in removing the front driveshaft out of the truck (while in 2HI) and taking it for a drive to narrow this down further? Is there any harm for the transfer case in doing this? Would there be an opportunity for the fluid from the transfer case to leak out during operation?

 

[Doubeleive]

99.999% of what the dealer did had nothing to do with vibration zero (but was not a waste of money, just regular maintenance)
as noted already pull the drive shaft and maybe "try" to have it rebalanced by a drive line shop or order a Dorman or try a used one from the junkyard.
"most" vibrations are caused by
tires/wheels
pinion gear (not the seal)
u-joints
drive shaft
output shaft
like others I have fought this myself, most of it was resolved with a new drive shaft., previous causes were pinion gear
poor alignment may cause wobble and be perceived as vibration this can range from 0~deathwobble

 

[Doubeleive]

j91z28d1 - thanks for the input and suggestion here. What color is your Z28?

Front driveshaft was/is the next thing on our minds as well. The dealer removed it from the first visit as indicated by marks on the bolts as well as chalk marks for indexing so not too afraid removing and replacing at home.

Does it may any sense/is there any harm in removing the front driveshaft out of the truck (while in 2HI) and taking it for a drive to narrow this down further? Is there any harm for the transfer case in doing this? Would there be an opportunity for the fluid from the transfer case to leak out during operation?

front shaft is pretty short unless the u-joints are toast it's probably not your cause

 

[Doubeleive]

sometimes the dealer will try and flip the drive shaft and see if that makes any difference but sounds like it did not

 

[j91z28d1]

j91z28d1 - thanks for the input and suggestion here. What color is your Z28?

Front driveshaft was/is the next thing on our minds as well. The dealer removed it from the first visit as indicated by marks on the bolts as well as chalk marks for indexing so not too afraid removing and replacing at home.

Does it may any sense/is there any harm in removing the front driveshaft out of the truck (while in 2HI) and taking it for a drive to narrow this down further? Is there any harm for the transfer case in doing this? Would there be an opportunity for the fluid from the transfer case to leak out during operation?

old user name from forever ago, still miss that car. it was blue and kinda rare manual. I do have a formula project car now that I can never find time to work on. haha.


as said above its is almost never the little short front shaft, but the long rear shaft.


the tell is you're not getting vibration in the steering wheel much and the frequency of it is higher than a tire. throw in the change in harmonics on and off throttle loading.

it's possible that you could spin the rear shaft 180deg in the pinion and feel a change, say at a different mph and the harmonics of it. but if it's really bad, it's just bad no matter how you put it in there.

 

[08TahoeVibes]

Bummer! Manual would have been quite rare for sure.

Not to discourage any other comments but you are explaining this well. Needless to say, we have been stuck in circles tracing this down so we appreciate the time and input here.

Can you make any sense of why the vibration would've gotten more noticeable from before the first dealership visit to now?

 

[Doubeleive]

Bummer! Manual would have been quite rare for sure.

Not to discourage any other comments but you are explaining this well. Needless to say, we have been stuck in circles tracing this down so we appreciate the time and input here.

Can you make any sense of why the vibration would've gotten more noticeable from before the first dealership visit to now?

if they flipped the drive line, yes. easy enough to flip it back

 

[08TahoeVibes]

I don't see any indication on the bolts of the u-joints of the rear driveshaft to suggest that they have been touched recently. They all look alike and not like they have had any tools put on them.

It goes without saying that you obviously know more about this drivetrain than I...

Having one of the front tire jacked up off of the ground; when I spin the wheel, the front driveshaft spins. Is this at all indicative of the 4WD operation? If the truck is in 2HI, is it expected that the front driveshaft to not be spinning or is it always spinning regardless of what is selected on the 4WD dial?

I suspect that it has to always be spinning for the gears to be in sync in the event Auto 4WD calls for power to be disbursed amongst the front wheels. That being said, there has to be a non-moving part that engages this when it's needed.

Always up for learning more about it!

 

[j91z28d1]

I don't see any indication on the bolts of the u-joints of the rear driveshaft to suggest that they have been touched recently. They all look alike and not like they have had any tools put on them.

It goes without saying that you obviously know more about this drivetrain than I...

Having one of the front tire jacked up off of the ground; when I spin the wheel, the front driveshaft spins. Is this at all indicative of the 4WD operation? If the truck is in 2HI, is it expected that the front driveshaft to not be spinning or is it always spinning regardless of what is selected on the 4WD dial?

I suspect that it has to always be spinning for the gears to be in sync in the event Auto 4WD calls for power to be disbursed amongst the front wheels. That being said, there has to be a non-moving part that engages this when it's needed.

Always up for learning more about it!

I think there's 2 or 3 different style transfer cases in these trucks. I honestly don't know which is which. the other guys know all the different part numbers and how they work. i think I have the same one you have. but not sure since I have the hybrid version that seems to always be a bit different.


but yeah, the oem u joints don't have grease fittings on them. depending on which one you have. they can also be held in with nylon, which makes them almost impossible to change without damaging the ears of the shaft.


I don't know all the details that are specific to these trucks. i just dealt with drive shaft vibration in my car from when I got it in high school for a good 10 years of owning the thing. so many shops, replacing parts with money I didn't have. I installed a 3.73 gear in the car cause I was just throwing a parts at it by then as I could save up for them. when I picked it up and it still did it, I took it back to the shop and a younger guy that installed the gear hopped in for a ride. Instantly he's like man, that's a drive shaft not my gear install. that lead me to drive shaft shops, multiple made and never fixed it even thou they all balanced perfectly on their balancers. finally threw a junk yard one in it and bam. first time the car was ever smooth from the first day I bought it.

drive shafts have been a pet peeve of mine ever since.

I mean anything is possible, I could be totally wrong. it's just a guess over the internet that sounds like it matches what I've dealt with.

 

[Fless]

I think there's 2 or 3 different style transfer cases in these trucks. I honestly don't know which is which. the other guys know all the different part numbers and how they work. i think I have the same one you have. but not sure since I have the hybrid version that seems to always be a bit different.


but yeah, the oem u joints don't have grease fittings on them. depending on which one you have. they can also be held in with nylon, which makes them almost impossible to change without damaging the ears of the shaft.


I don't know all the details that are specific to these trucks. i just dealt with drive shaft vibration in my car from when I got it in high school for a good 10 years of owning the thing. so many shops, replacing parts with money I didn't have. I installed a 3.73 gear in the car cause I was just throwing a parts at it by then as I could save up for them. when I picked it up and it still did it, I took it back to the shop and a younger guy that installed the gear hopped in for a ride. Instantly he's like man, that's a drive shaft not my gear install. that lead me to drive shaft shops, multiple made and never fixed it even thou they all balanced perfectly on their balancers. finally threw a junk yard one in it and bam. first time the car was ever smooth from the first day I bought it.

drive shafts have been a pet peeve of mine ever since.

I mean anything is possible, I could be totally wrong. it's just a guess over the internet that sounds like it matches what I've dealt with.

Now that's a lesson on how it can be good to get the shaft!

 

[j91z28d1]

Bummer! Manual would have been quite rare for sure.

Not to discourage any other comments but you are explaining this well. Needless to say, we have been stuck in circles tracing this down so we appreciate the time and input here.

Can you make any sense of why the vibration would've gotten more noticeable from before the first dealership visit to now?

I have no idea if ours has this or not, as I've never cut one open and am not touching the one in my truck till it either falls out or starts vibrating haha. but some have stuff inside them that can come loose.

https://www.jalopyjournal.com/forum/threads/cutting-drive-shaft-down-found-card-board-tube.388088/

 

[Doubeleive]

I don't see any indication on the bolts of the u-joints of the rear driveshaft to suggest that they have been touched recently. They all look alike and not like they have had any tools put on them.

It goes without saying that you obviously know more about this drivetrain than I...

Having one of the front tire jacked up off of the ground; when I spin the wheel, the front driveshaft spins. Is this at all indicative of the 4WD operation? If the truck is in 2HI, is it expected that the front driveshaft to not be spinning or is it always spinning regardless of what is selected on the 4WD dial?

I suspect that it has to always be spinning for the gears to be in sync in the event Auto 4WD calls for power to be disbursed amongst the front wheels. That being said, there has to be a non-moving part that engages this when it's needed.

Always up for learning more about it!

the axles & drive line will spin even if not engaged, the actuator that is screwed into the differential is what pushes the clutch/gear over to provide power when it is activated, when it's not everything is pretty much just free wheeling, you could probably grab it and hold it but I wouldn't recomend it lol

 

[blondie70]

Couldn't you jack all 4 wheels in the air and run front and rear seperately ? See where the vibration is ???

 

[Doubeleive]

Couldn't you jack all 4 wheels in the air and run front and rear seperately ? See where the vibration is ???

risky at best especially at any kind of speed and without a load no telliing if you would even feel it.
just runing it up to 35-40mph off of the ground is kind of sketchy

 

[petethepug]

If the vehicle was off the ground, their’d be no load on the drive train or suspension. You’d never hear a sound driving through the perfect road of thin air.

 

[08TahoeVibes]

I appreciate everyone’s comments, ideas, and knowledge share on this.

We are going to start with replacing the front driveshaft this week and see where we end up with that. More updates to come.