I've recently gotten an intermittant issue that I'm having trouble tracking down and I'm curious if anyone else has experienced this before. I've got a '98 4 door Sportage with a manual transmission and I've retrofitted the Warn manual hubs.

The issue does NOT occur when the hubs are unlocked in 2WD. It happens if the hubs are locked, regardless of whether the transfer case is in 2WD or 4WD. When driving, there is a loud "growling" that lasts for 3 to 5 seconds and then abruptly stops. The vehicle will run normally for 4 to 10 minutes, and then the loud growling will abruptly start, last for the few seconds, and abruptly stop. This is a regular occurence now whenever the hubs are locked in.

The front differential is full, there is no metal flakes in the fluid, the wheel bearings appear to be fine, the CV joint boots are in good condition and there is no knocking from "failed" joints when the steering wheel is turned. The front drive shaft is well lubed through its zerk fitting. I've been through the entire front drive visually, and pulling on shafts etc trying to find "play" in the system, and I'm not coming up with anything out of the ordinary.

Has anyone eles experienced this intermittant "growl" from the front drive system?