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gomi_otaku
gomi_otaku, Technician
Category: GM
Satisfied Customers: 3378
Experience:  VW Technician, VW FastTrack, VW Academy, VW Certified
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I have a 2009 Hummer H3T. It has just over 95k miles on it.

Customer Question

I have a 2009 Hummer H3T. It has just over 95k miles on it. It seems to run fine, but at certain speeds (for example 60 - 62 mph) the truck seems to have a shake to it. Almost like I'm driving over a rough patch of road. Not a really bad shake, but enough that you notice it.
Any ideas on a source of the issue? If so, what is the fix?
Submitted: 11 months ago.
Category: GM
Expert:  gomi_otaku replied 11 months ago.

Is it just sporadic, or just for a second, or does it vibrate constantly when you maintain that speed? And it goes away below and above that speed?

Customer: replied 11 months ago.
It only does it at certain speeds. Most frequent is between 60 - 62 mph. It stops if I slow down or accelerate and it continues if I hold that speed.
Expert:  gomi_otaku replied 11 months ago.

it's possible that your prop shaft (from the transfer case to the rear differential) either is developing a worn carrier bearing, or it may be unbalanced slightly. You can try unbolting it and rotating it a quarter turn relative to the differential (mark the original orientation so you can put it back if wanted). Or you can put weight onto the shaft to see if it changes the vibration at all, if you use a hose clamp (the screw fitting is the weight) then you can move it around the shaft forward or back, or rotate it around the shaft to change location and see if it changes.

Customer: replied 11 months ago.
Thank you very much for your response. When trying the hose clamp is there a particular position on the shaft that I should try first? If it is the carrier bearing, could I replace that on my own or would it be better for me to have it done? What kind of cost am I looking at to have it done? And are there any other possibilities for the issue?
Expert:  gomi_otaku replied 11 months ago.

It seems like, since it is based on speed and not on engine RPM, then it is the wheels, differential, or the prop shaft- the prop shaft being the most likely suspect. The carrier bearing can sometimes be beaten off with a hammer, and a new one pressed (beaten) into place. You would have to remove the shaft to do so.

As for putting a weight on, I would inspect and see if there are weights welded onto the shaft (square or rectangular blocks) and maybe start opposite them.

Customer: replied 11 months ago.
There are two rectangular blocks located on the shaft. They are in line with each other, on either end of the shaft (One on each end). Should I start with just one hose clamp or use one on either end of the shaft where the weights are located?
Expert:  gomi_otaku replied 11 months ago.

Don't make it too complex- just try one on one end of the shaft, see if that changes anything, and every time you go out move it around the shaft slightly, and then try the same process at the other end.

You can take the shaft completely off and send it out to a shop to see if it is balanced, they have specialized equipment to spin it up on similar to a tire balancing machine.

Customer: replied 11 months ago.
I will give it a try and let you know how it goes. Thank you.

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