Join Date: Aug 2008
Location: Near Gainesville, FL
Feedback: 0 reviews
Okay, just picked up the Jeep. Drove it 20 miles home. Issue is resolved, for the moment.
Again, I have a 2.5" TF shock and spring lift. I installed the lift myself around 75K miles. New 34" GY MTR/K's at 79K miles. The rhythmic, pulsing, deep throated driveline hum started up around 95K I'd guess. I'm at 107K right now.
I talked to the tech before and after repair. Oddly enough considering I'm in Florida, he's a rock jockey. He builds and wheels rock buggies as a hobby. Owns three of them, so he's actually qualified to figure this out. For everyone's benefit I'm typing out the writeup from my receipt from the service.
"Customer states that there is a whinning noise from the vehicle at about 45 mph. Road tested and heard loud growling sound and whining sound on accell. Found front drive shaft wobbling. When inspected vehicle in air found both inner axle seals appear to be leaking and fluid level low. Rear pinion seal leaking and rear pinon shafts loose. Attempted to tighten pinion shafts but then noise got louder Removed front and rear diff covers to check gears and bearings. Found front ring gear worn badly and pinion bearing failed. Also carrier bearing severely pitted due to metal in oil. Replaced ring and pinion gear and all diff bearings and seals. Replaced damaged diff lock sensor and reassembled. Rear axle pinion bearing loose and carrier bearings pitted from metal in oil. RR axle seal leaking, pinion seal leaking. Replaced pinion bearing and carrier bearing. Replaced both rear axle seals. Reset Pinion Depth and backlash. Road tested to verify repair."
He showed me the front ring and pinion gears he took out. He had to explain it, but once I understood what I was looking for the wear was obvious. The rear gears were fine. The dealer had been in the front diff before for another issue some time ago, and the unofficial consensus was that they had not set the pinion depth properly at that time, resulting in premature wear. Or an oil issue because it doesn't flow well back to the pinion bearing.
So my noise was diff related. One more option to throw into the mix.