Replaced the timing chain on my 2000 ranger with a 3.0l and a standard trans 2 wheel drive. i messed up the gasket between the timing chain cover and the oil pan I don`t want to replace the whole oil pan gasket so I cut it off even with the block can I use a l silicone sealer instead of replacing the gasket?

 

It will probably start to leak and let go, that's quite a space for the RTV to fill.
I suppose if you were to totally let it set up before driving, it may last.

I would get another pan gasket and custom cut the section I needed, using a thin film of ATV on both sides.
I would then leave it for a couple of days for the RTV to totally cure.

Paper gasket material can also be had, you could build up layers with RTV in-between until it was tight.