The timing cover doesn't have a gasket, per se. Only RTV is used around the cover perimeter so if you have a bad oil leak it is most likely the front main seal. It can be replaced with the cover still on the engine - you can find the appropriate Miller tools on eBay and other places like that. You'll need Tool #'s 8511, 8512, and 8348 to take the old seal out and put the new one in.
The other option is to take the front cover off, replace the gasket for the coolant galley (one small, almost oval gasket), replace the front main seal on the crankshaft, put new RTV around the edge of the timing cover and replace.
As for the tensioners...I don't know that you gain anything by replacing them unless they are causing significant problems right now. When I swapped engines I had the donor down to just the long block which meant taking the timing chains and tensioners out. I did it with the engine on a stand - trying to do all that with the engine in the Jeep would be a nightmare in my opinion.
Here's what it looks like: The tensioners are at the lower left and upper right. The arms that push against the guides need to be compressed while you put the tensioners in - like I said, doing it with the engine at eye level was enough of a job. Doing so with the engine in the Jeep would be a challenge.
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Just replace the front main seal to fix the oil leak and go from there. You'll save yourself a LOT of work. :imo:
Bob
