Howdy Scotty,
I have a 2006 Jeep Grand Cherokee V6 4x4 automatic with 140k miles. I started to notice a whining noise and felt the slight vibration through gas pedal only when I accelerate above certain RPM, as soon as I let off the gas, the noise is gone. After driving 1k miles, it became louder, so I got a shop check out the problem who replaced the pinion/bearing kit of the rear differential. They said the diff was leaking and wore the gears. Now the noise is significantly reduced but is still there. The mechanic said the both U-joints of the rear drive shaft are bad. Could it be the bad u-joint caused the pinion to be worn so I still have to fix this upstream problem?
Worn out driveshaft components can cause weird noise yes. Also check engine for vacuum leaks, etc.
Thank you very much for your comment. Will the worn drive shaft cause the pinion to go bad again?
it could
Hi Scotty and fellow gurus,
This is a follow-up post on my a 2006 Jeep Grand Cherokee V6 4x4 automatic with 140k miles. I started to notice a whining noise only when I accelerate above certain RPM, as soon as I let off the gas, the noise is gone. I replaced the pinion gear on my rear differential and the noise has lowered but is still there. I can feel it coming from the center/front of the vehicle and would slightly resonate my pedal and even steering wheel when I accelerate. My mechanic pulled out the rear drive shaft, and told me he still heard the noise so he thinks it is the transfer case. But I worry that it could be the front differential instead.
If I disengage the front drive shaft, and still hear the noise, could that really indicate it is the transfer case and not the front drive line? Or the gears in the front differential will still be rotating/engaged when no power is being sent by the transfer case, thereby making noise?
Holy cow. Wish I knew about this earlier. I was seriously thinking about taping my phone to the undercarriage haha. Thanks a ton!
call around. There might be auto part stores that loan these out.