2007 Cad Escalade - 6.2L Noise Driving At High Speeds

[TAMCNEILL]

I have a 2007 Cadillac Escalade EXT with the 6.2, 124150 miles

At speeds of 50mph and high there is a type of vibration noise centered in the middle front of the vehicle from inside. It can't be heard at idle or from the outside as much as I can tell, but while driving it comes when on the throttle no matter how heavy or light you can hear a noise when the throttle is depressed. Once you let off the throttle completely it goes away. The faster you drive the louder it gets, but once the transmission downshifts the engine drowns the noise out until the upshift, it's not robbing any power, fuel mileage, or draining the vehicle in anyway. I've checked drive components, ignition components, for loose parts and have come up with nothing. I've had the oil change tires replaced and rotated and still cannot find this noise. I've checked bushings, bearing, brakes, fluids, and I am not finding this noise.

I'm wondering if any of you have experienced something of this nature and if so where did you look.

[steven kiser]

i'm going with it's a load noise and i see a lot of front differential issues in g.m's of this vintage. put it up in the air, by pass the automatic engagement of the front wheels and play with the gas pedal. i think the way to by pass these is to start in 1'st gear and then manually move it up to second. shouldn't have to go any further. if you wind it up in drive the front wheel will engage so hard you'll think it's going to jump off the lift. sounds like a transfer case or front diff. if this is the case i stopped trying to rebuild the diffs years ago because the hubs freeze on the shaft and are almost impossible to remove without damaging them. another tip here, when i deal with any noise issue in the front end of gm's of this style and the mileage is in excess of 70k i try to include the front wheel bearings into the mix or at least make darn sure the customer knows that they are close to their fail point and will cause a pedal drop out under 5mph along with a howling noise while slightly turning the wheel. the last thing you need is to replace a front diff and then within a few months a wheel bearing starts to howl.

[jbadenoch]

I agree with steve, have heard similar noise on these, turned out fr diff. If you have wireless chassis ear would certainly help. Good luck

[fortknoxx]

We get these in often. It starts out as the bearings in the front diff, by the time it is brought to us the r&p is wrecked.

[TAMCNEILL]

Thanks for all the tips, I had the front diff checked it is good. In fact, the transfer, transmission and rear diff seems to all be in good working condition as well. One thing I didn't mention is I had the Rear main seal replaced in april maybe this will help. The noise is still there, at speed when coasting there is no noise at all very quiet. Again thanks for all the tips and should someone have any other ideas I'm open for suggestions.

Have a great Holiday Season.

[steven kiser]

It sounds like a load noise to me. With the added rear main seal information i would look closely and the alignment of the exhaust. It may be hitting when accelerating. This type of noise usually can be duplicated by applying the brake when it's in drive then giving it a bit of gas. I want to say brake stand but that's an extreme.

Make sure all is happy happy where the trans and engine meet. Heck i've had noises from transmission dip sticks hitting a fire wall.

[92zman]

i would try to check the flywheel and bolts. Make sure all are tight. Really o would check all the bolts.