Oil level good. Change the oil regularly?? Those are some causes. A good oil using recommended weight for your engine and climate. Try an additive there are many check with your local parts store.
89 2.5 TBI, 4" RC lift, 1" Booms, SYE, Adams Driveshafts front and rear, Ford 8.8 with 4:88s, BFG 33X12.50X15, and a ton of other stuff.
AF Jeep Club Tail Number 184