my 4-wheel drive knocks?

[94 Ranger]

ok when i run the truck in 4-wheel...it has the auto-lock hubs....it knocks like hell?...almost like the it is skipping teeth or something???..
You guys have any ideas what i should check first?...i just got this truck

 

[dennis461]

Use a large screwdriver or crowbar to check for loose u-joints. One at each wheel/hub and the center one.
If they are tight, pull the front wheels off and auto hub covers.
Inside should be grease, not dirt or rust.

Check front driveshaft, DS, for looseness (some little looseness is to be expected for the DS slip joint)

Pull the fill plug from front diff and look inside for metal shavings.

Other checks will take more tools and skill so try this simple stuff first.

 

[94 Ranger]

ok that sound pretty good i will try that this weekend...thanks very much