I had the privilege of having the top of the black tank crack, overflow, and generally make a mess
I was in NO-where S Dakota and had some time on my hands. I did not know what I would find, so in the basement area above the tank, using a saws-all cut the lines going into the tank so I could drop the tank with lines still attached to the tank top. About 6" stub sticking out of tank top.
Used a epoxy material and fabric bought at the lumber yard to seal tank top and then screwed the board onto the tank top.
Re-installed tank, used rubber coupler things with hose clamps on both ends to re-connect the piping. Used rig 4 more years, no problems.
Was easier to do this than try and replace the tank.
Link to 90 tank repair pics:
Been there, done that, got pics.....
Since them I have discovered Eternalbond tape and it would have worked instead of the epoxy.
2012 Ram Laramie 3500 DRW 4x4 3.73 Tow Max Pkg B&W Companion 60 gal RDS aux fuel tank. 2014 Montana 3150RL, 2 A/C's, Leather, 6 Point Jacks, Splendede WD2100XC, Mor/ryde X-Factor, Duravis 250 tires with TST 507RV monitors. 2 x Honda EU2000's