Likely cause of oil leak?

Any suggestions as to what would be leaking or worn out to allow oil to be leaking out the bottom of the bell housing (Quite a regular flow under load) ? (Engine Oil)

 

Rear main seal.

 

Hmmm. Assume I can take off the sump and that the seal is within the rear main , or does it have a seperate carrier?

 

first check the PVC valve that it is working and no pressure is building in the engine.

 

Yep. Check the PCV and make sure that oil is not draining down from the top of the engine. Valve covers and rear manifold seal are other possible locations for a leak, but the rear main is most likely.

To reach the seal, you remove the oil pan (sump) and remove the rear main bearing cap. There's a groove machined into the rear cap and the block for the seal. You have to push the top half of the seal out from between the block and the crank, then push in the new seal. The TSM advises you to loosen the other main caps too - there's a procedure in the TSM.