Regear -- Now a Hum in the Front End

48HMSFAN · 2011-08-22T02:06:00+00:00

Just had my 3rd-gen regeared (4.10 to 4.88 with ARB Front and Rear Lockers), and now there is a constant hum from the front end anytime the transfer case is in 2H (Auto Trans). The noise goes away when the transfer case is 4HI, 4LOW, or N regardless if the engine is running or not. This noise can best be described as what you would hear from oversized mud terrain tires cruising at highway speed although on a lower scale. The noise starts at approximately 20MPH and can be heard until about 60MPH -- unsure if the sound goes away, or has just been overtaken by road noise. The sound continues through stopping until about 20MPH, and almost sounds akin to a manual transmission vehicle downshifting to use the engine to brake. I am running 265/75/16 Michelin LTX A/T2 tires. Obviously this noise wasn't a factor before the regear, and the tires have never had much noise. After about 600 miles I started to get a creak/click from the front right. Maybe a bad C/V, and don't necessarily think that it is associated with the re-gear. As for the differentials, I got them from East Coast Gear Supply fully assembled with ARB lockers. I have been told the cause of the hum is that the axles/drivetrain is always turning and as momentum builds it will eventually transfer to, and turn, the front diff; and that the reason the noise goes away when engaging 4WD is now the diff is engaged and under load. Not a complete novice when it comes to diagnosing mechanical problems, but usually leave the repairs to the pros. At some point my time (and sanity) is worth more then money. Thoughts, comments?!?! Was ready for the increased RPMs, and engine noise associated with; but this was unexpected and I don't know if it's "normal." Would an improper "shimming" cause this issue? Thanks for any input you can provide.