grinding in 4wheel

[sakundiak]

91 sport, 5spd, when in 4wheel drive makes a kind of grinding noise, low growl, eveything work fine but noise doesn't sound healthy Thanx

 

[DeRocha]

Do you have auto hubs or manual, and where are you driving in 4x4 (off road, snow, or on-road)?

 

[sakundiak]

auto hubs, all of the above, makes the loudest noise on-road, well grid

 

[DeRocha]

Ok.. How long have you owned it and when was the last time the U-joints and hubs were checked? If is common to have problems with autohubs and stub axle U-joints. Over time the U-joints get dried out (they only move when the hubs are locked). 4x4 should only be used Off-road, or on wet roads... The tracktion on dry road is HUGE and can cause drive train breakage.

 

[sakundiak]

4 years, checked within the last year, i think about 7 months ago, everything came back fine, the 4x4 is only used on the muddy grids that i take home from work, its gumbo like mud, and in the winter

 

[DeRocha]

Where does the sound appear to come from? Does it go away when you disengage 4x4 (but still have the hubs locked)? If the noise is centered under your vehicle have you check the T-case and diff fluid levels?

 

[sakundiak]

it appears to come from the center front, fluid levels are good and clean, it quits when 4x4 disengages, don't quite understand (but still have the hubs locked) they unlock automatically don't they

 

[DeRocha]

After you disengage 4x4 the Autohubs will unlock once you travel 10 feet in the opposite direction. That being said once you engage 4x4 and then shut it off (but don't reverse direction) the autohubs will still be locked and the front drive shaft, diff, and axles will all be moving... I would remove your hubs and check them out to see if anything looks out of place.