There may be an access plug there. As far as a flush I have never done one but Seafoam seems to be the choice here.
I also don't have any experience inside the 2.5 but on other engines yes there should be a plug.
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