to get at the back bolts the two front subframe bolts have to be removed and the rears loosened. this allows the subframe to droop and give access to the oilpan by wiggle and feel. thats the way...but on my rusty 81 4000s the bolts all broke off! this causes the complete removal of the subframe and gives unrestricted access to the bolts. ymmv mike 86 5kcdtq, tap chip sjm spring 84 5ks 84 5ksw many cyclops bicycles