if the timing chain cover is leaking, resealing it costs only 15 bucks for parts from napa. the head and pan do not have to be removed.
toyota does not use a gasket for the oil pan. they use OE silicone called FIPG. if you used one, thats where the leak is.
Its possible the end of the head gasket was tater'd when installing the cover. that can cause a leak.
for that job, you dont have to pull the cover
