do you have any pics? it's hard to speculate, but if your HB came off, you are going to want to check it for damage where it comes in contact with the oil seal. You will also want to check your seal to make sure it isn't damaged. If you don't have the bolt, you will have to get the new one. you should also check to see if the key is still in the crank. you can also download the FSM(factor service manual) and it should be able to tell you what you need. mitsubishilinks.com will have it.

'88 Raider. 2.6L dead...2.4L swap in progress, AT, 33's, 2 bouncy seat,AC, CC, 2.25 exh, 2" Tbar, 2" BL, rear DB, rear LSD,4.90's, SW hubs,gen2 uca's, KYB shocks, snorkel, elec fan, MSD.

'99 chev k3500 crewcab
'15 Subaru XV
'03 BMW i325