I really don't have very frequent opportunities to put my Burb in 4WD, but have noticed something which may be an indicator of a problem.

I usually run in 2WD and when pressing the 4WD Auto or 4WD hi, it shifts promptly and quietly. However, when I go into 4WD lo, it takes about 10-15 seconds, and I can hear a rather firm "clunk", when it engages.

Is this normal with an older Burb (2003/142Kmi) ?

 

It may be the sign of your actuator dying.

It may also be the notorious Gm driveline clunk.

 

Thank you for your reply.

 

Just a followup on this...

I've found that I have the NP8 Transfer Case (with the 4L60E transmission).
Does anyone know what the Low Range Gear Reduction is for that Case ?