M1009 4 wheel drive noise

[frankieg]

My 1986 M1009 has a light whining noise when going down the road (not a dry road, I only use 4 wheel on slick roads) in 4 wheel drive. The 4 wheel drive works great, all u-joints are good, no leaks on front differential or transfercase. All fluids are full (in transfercase, transmission, & differentials) Someone told me that this is a normal sound. It sounds like it may be coming from the transfercase or front differential. Once it is back in 2 wheel drive the noise is gone. Is this a normal sound? Has anybody else's M1009 make this noise?
Thanks

 

[mikelee]

the whine

Mine does this also

 

[cleb]

Mine made that noise as well, pretty sure its normal.

 

[gaunt1969]

its the sound of the chain in the tcase and is normal