2007 Yukon SLT vibration

[kgwmu]

Hi,
First post here and I'm looking for some help on a vibration in my 2007 Yukon SLT. It has the auto leveling suspension. I do have a "service suspension system" light on, had it checked and it is a bad ground. I also have the "service park assist" light on, that I believe is just a bad sensor.

The Vibration:
It doesn't occur the same everyday. Sometimes it will be in the front making my steering wheel shake and other times in the rear where I feel it in the seat. Sometimes I have the vibration in both spots, but most of the time it is either in the front or the rear. I can feel it as low as 45 mph (it is very faint), but I can really feel it when I am going about 75 mph. I also tend to notice it a lot if I'm going 80 mph and let off the throttle.

Vehicle history (since April 2014, when I bought it):
- 150K miles
- replaced 2 u-joints on rear drive axle
- had stock wheels w/tires (vibration existed)
- traded for other wheels & tires (vibration still existed)
- got brand new tires (vibration existed)
- vibration got worst, had tires re-balanced, vibration went back to lesser vibration

Then we are at today! I'm convinced that it is not wheels/tires due to the changes that have been made, and the way it seems to move around. I'm looking for anything to look at if you have had vibration problems similar.

thanks,
Kevin

 

[kgwmu]

Nobody has had a similar problem??? Just looking for some direction on what to check.

So I was towing an open car hauler trailer (empty) and I noticed that the rear was making kind of a shudder type sound while driving. So this makes me more convinced it is something not tire related.

What are some wear parts I should look at in the rear end?

 

[992dr]

Unfortunately, I have gone through all of this as my 07 has had a shudder/vibration as well. I brought it to a shop in Dec and it has gotten worse ever since they put there hands on it. I'm almost used to it now.

What I had originally thought it was for me was my converter. Since it only happened at lock up around 43mph and up. What I wasn't aware of then but am now is that our transmissions have what's called PWM = pulse width modulation. The traditional way of testing to see if it is your converter is no longer affective, drive at highway speeds and tap the brake and watch the RPMS go up. This is where I can kick myself in the a$$ because the shop instantly said "its your converter" and I fell for it.

Has it thrown any codes besides the ones you had mentioned?

You could have a misfire
It could be a transmission issue

Do you have a mechanic that has experience with a scan tool? Tech II or Modas scan tool?

 

[Labman2012]

I am having a similar issue and I am starting to think my vibration is in the rear end. I am close to just pulling the center section and having it rebuilt.

---------- Post added at 03:34 PM ---------- Previous post was at 03:31 PM ----------

I have changed all of the front suspension, I have two sets on wheels and tires and I have also changed the u joints. I have flushed the trans and can't think of anything else it could be except the rear end. I do have a little play when I take off which is another reason why I think it may be the rear end. Do you have play when going from reverse to forward?