I can't comment on the specifics of your vehicle but keep in mind that
regardless of strength, anything attached to an up/down tailgate will make
raising and lowering it a bitch. A tire and a 5 gallon gas can will add over
100 pounds of dead weight. While there may be more than enough support while
the gate is up and locked there will be a huge stress on both the gate and
the hinges when it is lowered and supporting the full dead weight of a tire
and a gas can. Any extra stress to the gate in this position, such as
standing on it, may warp it and make it unable to lock back into a closed
postion. If you have a gas can that is not perfectly sealed you will also
leak gas every time you lower the gate. There are carriers available that
can be attached to the corner post of the truck bed and swung out of the way
of the tailgate for normal operation. I don't know where to send you but you
should be able to hunt one down with an internet search. I had one on an old
K5 Blazer and I see them on Jeeps and some pick ups. It may mean
modifications but in the end will be well worth it.

Bob Walker