drivetrain noise in 4wd

[ARJeepman]

I'm working on 86 GW with 228 t/c. Vehicle has noise when engaged in 4wd. Sounds like a metal to metal squawk that sheetmetal would make. It goes away whilecruising,but get's lod on accleration. Turn the vacuum switch back to 2wd and the noise quits when the t/c disengages. Rough roads seem to make it worse. Truck has 159,000 miles and I don't think anything has been replaced as far as front shaft u joint or cardin joint. Help me out here please,it's hunting season!!!!!! Thanks!

[Heimeken]

make sure that the vacuum actuator is putting in 4wd all the way. Besides that, sound like you may have a wornout chain.

[ARJeepman]

The unit works fine in 4w lo and hi...just makes a loud squeaking noise. This just started...it didn't slowly work up to,just all of a sudden. I don't hear any chain slap at all. Thanks for your reply!

[jeepguzzi]

Make sure the front driveshaft is not hitting something, like the inspection cover of the tranny, or a branch that may be lodged against it.

You might have a bearing or a u joint going out.