Ride stops shuddering when put into neutral...

[FromRGV]

My '07 Yukon has been vibrating considerably lately and I'm not sure where to start. The problem is mostly while cruising when the truck slows down and tries to downshift it will shudder.

I took my truck to several shops and had different reasonings.

1st Shop gave it a maintenance tune up but the vibrating continued and mentioned it was the motor mounts.

2nd Shop changed my differential fluid and checked the gears but the vibrating continued and said it was the tranny mount.

3rd Shop changed the driveshaft u-joints and mentioned all mounts are okay and suggested I just drive it until the transmission gives out.

I was doing just that until last night I was driving around 80mph when I noticed a similar type of shudder that started happening that didn't stop, even in park, until the following day.

I checked online and a 2013 post mentioned to put it in neutral to see if it stopped, which it did, thus probably being the torque converter. The thread then drifted to mentioning that the Ranger Afm disabler probably fixes the problem.

Anyone with a similar experience know where to start?

 

[kbuskill]

Active fuel management will definitely cause a shudder/vibration when in V4 mode but giving it throttle should make it stop if that is your problem.

 

[iamdub]

I'm with Ken. Let's hope it's just the AFM crap doing it's crappy thing. The Range module is a quick and easy way to disable AFM and may fix it. For a few more dollars, you can get a custom tune to turn off AFM as well as improve throttle response, shifting characteristics, power, etc.

I notice mine shutters if I'm rolling at a steady 20-25 MPH and it goes into V4 mode because the RPM is lower and it's "missing" half it's cylinders. It shutters worse just as I'm coming to a stop from those slow speeds, too.

Put your DIC so you can see what mode it's in and do some slow (15-25 MPH) and steady cruises down a non-busy street and see if you feel the shuttering and if it's in V4 mode when it does it. Slowly come to a stop and, again, take note of the shuttering and cylinder mode. It should shutter a bit worse then suddenly stop right before you stop the car, and the DIC should display "V8" mode about half a second after that.