Need help ASAP with 97 Yukon please

[jongraack]

I have a 97 yukon 2dr with the 5.7 vortec 4-wheel drive. No mods and well maintained.

Just recently it developed a bad humming noise from the rear or center possibly. I can also feel a vibration in the gas pedal. The noise is noticable at about 25mph and gets horible around 45mph and higher. At about 35mph and higher if I let off the gas and then press back on the gas with normal weight it feels like I'm pulling a trailer with slack. It shudders.

Tires are balanced. Allignment has been done. Driveshaft has no twist play. Can't tell if U-joints are good or not just by looking. I need help please??? Any assistance will be much appreciated.

Thanks!!!

 

[lesterl]

Rear end....... my .02

 

[jongraack]

Rear end....... my .02

Thats what I was thinking too, just because of how it feels but I am not familiar with the this side of the auto industry, so I am not to sure. Is there any way to tell/test? Will there be any play in the rear tires with the rear end jacked-up off the ground? Thanks for the reply too!!!

 

[lesterl]

If you get it on the highway, giving gas it will make noise at one pitch, let off gas (coast down) it will make different pitch (front side of teeth/ back side of teeth on gears.)

 

[ma87k5]

If noise gets louder when driving faster and stays constant whether foot is on or off the gas while driving then I would look at your pinion bearing or diff bearing. They could slow you down if bad enough. Also if your drive shaft u-joints are factory you should change them while you are there. I've had bad u-joints and not know it til I took them apart.